
Qass G B I Q 2 . r 

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Professional Paper No. 52 Series { J; JX^U'^rA 

DEPARTMENT OF THE INTERIOR 
UNITED STATES GEOLOGICAL SURVEY 

CHARLES D. WALCOTT, Director 



GEOLOGY AND UNDERGROUND WATERS 



^ OF THE 



ARKANSAS VALLEY IN EASTERN COLORADO 



BY 



]N^. EC. r>^RTO]sr 



A^ 




WASHINGTON 
govern:ment printing office 

1906 . ' 



^/■*:t»i;'^*' 



Professional Paper No. 52 



8flrie<! / ^' Desoriptive Geology, 89 
^^■^^^n 0, Underground "Waters, 55 



DEPARTMENT OF THE INTERIOR 
UNITED STATES GEOLOGICAL SURVEY 

CHARLES D. WALCOTT, Director 



GEOLOGY AND UNDERGROUND WATERS 



OF THE 



ARKANSAS VALLEY IN EASTERN COLORADO 



BY 



:n^. h. jdj^^rtojs^ 




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WASHINGTON 

GOVERNMENT PRINTING OFFICE 

1 906 



-A^ 



NOV 19 1907 
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CONTENTS. 



Page. 

Introduction 7 

General configuration of the region 8 

General geology of eastern Colorado 9 

General relations 9 

Structure 9 

Formations 10 

ieology of the Arkansas Valley region 12 

Stratigraphy 12 

Cambrian system 13 

Ordovician system 14 

Manitou limestone 14 

Harding sandstone 14 

Fremont limestone 14 

Carboniferous and Triassic( ?) systems 15 

Millsap limestone 15 

" Red Beds " 16 

Cretaceous system 21 

Morrison formation 21 

Comanche series 25 

"Dakota" sandstone 25 

' Graneros shale •. 27 

Greenhorn limestone 27 

Carlile formation 28 

Timpas limestone 28 

Apishapa formation 29 

Pierre shale 30 

Fox Hills sandstone 32 

Laramie formation 32 

Cretaceous (?) system 33 

Arapahoe formation 33 

Poison Canyon formation 33 

Denver formation 34 

Cuchara formation 34 

Tertiary system 34 

Monument Creek formation 34 

Nussbaum formation 34 

Quaternary system 35 

Alluvium 35 

Dune sands 35 

Igneous rocks 35 

Manitou embayment 36 

Canyon embayment 38 

General structure 38 

Garden Park area 39 

West of Canyon 40 

3 



4 CONTENTS, 

Geology of the Arkansas Valley region — Continued. Page 

East side of Greenhorn Mountain 43 

Geologic history 45 

. Cambrian 45 

Ordovician 46 

Silurian-Devonian 46 

Carboniferous 46 

Cretaceous 47 

Post-Laramie conditions 49 

Quaternary 50 

Underground waters 50 

" Dakota " sandstone waters 50 

General conditions 50 

Flowing wells 52 

Nonflowing deep wells 62 

Unsuccessful deep borings 68 

Source of the " Dakota ' ' water ■ 73 

Depths to the " Dakota " sandstone 74 

Area of flow 75 

Pressure or head 76 

Quantity. 77 

Quality '. 79 

Waters of the " Red Beds " and the Morrison formation 82 

Waters of the Laramie and associated formations 83 

Waters of the later Tertiary deposits 84 

Waters in the dune sands 84 

Index 85 



ILLUSTRATIONS. 



^ Page. 

Plate I. Map of central-western United States, showing area treated in this report 7 

II.' Relief map of the drainage basin of Arkansas River in Colorado 8 

III.' A, The High Plains in eastern Colorado; B, view on the Great Plains in eastern Colorado. . 8 
IV.- A, Haystack Butte, Pueblo County, Colo.; B, Apishapa Canyon northwest of Thatcher, 

Colo 10 

V.' A, "Dakota" hogback at Canyon, Colo.; B, "Dakota" hogback ridge southwest of Can- 

}'on, Colo 12 

Yn Geologic map of the Arkansas VaUey in southeastern Colorado Pocket. 

VII. Geologic sections across southeastern Colorado _ 14 

VIII.'' A, Quarry in Harding sandstone northwest of Canyon, Colo.; B, Fremont limestone north- 
west of Canyon, Colo 16 

IX; A, Vertical lower "Red Beds," Garden of the Gods, Colo.; B, the stone wall on Purgatory 

River west of Trinidad, Colo 18 

X. A, "Dakota" sandstone in hogback ridge southwest of Canyon, Colo.; B, bone-bearing 

sandstone in middle Morrison formation in Garden Park north of Canyon, Colo 22 

XL A and B, The stone wall on Purgatory River west of Trinidad, Colo 24 

XII) A, Greenhorn limestone near Thatcher, Colo. ; B, Timpas limestone in quarry southeast of 

La Junta, Colo — 26 

XIII. Characteristic fossils of Niobrara and Greenhorn limestones 28 

XIV. View along Arkansas River; basal Timnas limestone on Carlile sandstone 30 



ILLUSTRATIONS. 5 

/ , ^'^se. 

Plate XV. A, Tepee buttes in Pierre shale north of Nepesta, Colo.; B, Timpas limestone on Carlile 

1, sandstone northwest of La Junta, Colo 32 

XVI. Map and cross sections showing geologic relations in the Manitou embayment and north- 
ward - - 36 

XVII. ^4, Vertical "Red Beds" near Colorado City, Colo.; B, Morrison formation on granites near 

Grape Creek, southwest of Canyon, Colo 38 

XVIII." Map and cross sections of "Dakota" and associated formations in the Canyon embayment, 

Colo 40 

XIX. A, Shale member lying between base of Fremont limestone and top of Harding sand- 
stone on mountain slope northwest of Canyon, Colo.; B, Harding sandstone on gneiss 

and schists northwest of Canyon, Colo 42 

XXi A and B, Conglomerate at base of "Red Beds" north-northwest of Canyon, Colo 42 

XXI.' A, Two Butte in southwest Prowers County, Colo.; B, water hole in "Dakota" sandstone 

near Thatcher, Colo 44 

XXIIl;^ Map and cross sections showing relations of " Dakota" and associated formations on east 

side of Wet Mountains, Colo 46 

XXIII. Section showing relations of wells in the Arkansas Valley from Pueblo to Coolidge 50 

XXIV.' A, Artesian well on ridge south of La Junta, Colo.; B, flowing well at Rocky Ford, Colo. . 54 

XXV; Map of artesian conditions in the Arkansas Valley in southeastern Colorado Pocket. 

XXVI.' Map showing structure of " Dakota ' ' sandstone in eastern Colorado 56 

XXVIL' Artesian well 10 miles south of Portland, Colo 62 

XXVIIL' Map of part of the Arkansas Valley showing altitude of head of water in "Dakota" sand- 
stone 76 

Fig. 1. General section showing thickness of strata overlying the "Dakota" sandstone in the Arkansas 

Valley 51 

2. Diagram of apparatus for illustrating the declivity of head of liquids flowing from a reservoir. . 52 



U. S. GEOLOGICAL SURVEY 



PROFESSIONAL PAPER NO. 52 PL. I 




M E X I 



MAP OF CENTRAL WESTERN UNITED STATES, SHOWING AREA TREATED IN THIS REPORT 



oO 100 





200 



300 miles 



GEOLOGY Am UNDERGROUND WATERS OF THE ARKANSAS 
YALLEY IN EASTERN COLORADO. 



By N. H. Darton. 



IISTTRODUCTION. 

In the vallej^ of Arkansas River in southeastern Colorado there is an area of 
considerable extent in which artesian flows are available. During the last ten years 
numerous wells have been sunk to develop this important resource and, in most 
cases in the lower lands, abundant water supplies have been obtained. The princi- 
pal water-bearing bed is the "Dakota" formation, which consists of two sheets of 
porous sandstone separated by a small body of clay and overlain in the greater 
portion of the area by a mass of impervious shales. The sandstones receive their 
waters from rainfall and from the sinking of streams along the foothills of the Rocky 
Mountains and on some of the higher slopes south of the Arkansas Valley. In the 
passage of this sandstone underground, the watei;s which it contains are held down 
by the overlying shales, but, as some of the sandstone outcrops are at relatively 
low levels to the east only a moderate head or pressure is sustained. On account 
of this low head, artesian flows are available only in the lower lands, and one of the 
principal objects of this investigation has been the determination of the area in 
which flows are to be expected. The "Dakota" sandstt)ne and associated forma- 
tions do not Jie level, or even slope regularly to the east, but are flexed into low 
arches and shallow troughs of considerable complexity of configuration. Accord- 
ingly, in investigating this source of water supply, it has been necessary to ascertain 
the structure and distribution of the various formations in order to indicate the 
variations in depth to the water-bearing stratum. The principal results of these 
investigations are set forth: (1) In the geologic map (PI. VI), which shows the dis- 
tribution of the formations on the surface; (2) in the map, PI. XXV, which shows 
the depth to the water-bearing horizon, the area in which flows are expected, the 
head of the underground waters, and other features, and (3) in the cross sections 
(Pis. VII and XXIII), which show the principal imderground features. The 
investigation has been in progress for several years and is an extension of the 
preliminary examination of the region by G. K. Gilbert in 1894 and 1895. '^ 

a Gilbert, G. K., tTnderground waters of the Arkansas Vallej in eastern Colorado: Seventeenth Ann. Kept. U. S. Geol. 
Survey, pt. 2, 1S96, pp. 1-51, Pis. LVl-LXVII. 

7 



8 ARKANSAS VALLEY IN EASTERN COLORADO. 

For the western portion of the area the maps and texts of the Pueblo, Elmoro, 
Walsenburg, Spanish Peaks, and Pikes Peak foUos have been utihzed as far as 
practicable. For the central and eastern portions the larger features of the geology 
have been specially mapped, and considerable detailed mapping has been done in 
the region south and southeast of Canyon and Colorado Springs. In the field work 
I have been assisted by ^Mr. C. A. Fisher, who has examined in detail the Xepesta 
quadrangle and conti-ibuted numerous other data. Dr. W. S. Tangier Smith and 
Messrs. C. E. Siebenthal and W. T. Lee have made observations in certain areas. 
Much valuable information respecting wells has been furnished by Mr. William 
Archer, of the Atchison, Topeka and Santa Fe Railway Company, and !Mr. C. H. 
McVay, well driller at Rock}- Ford. 

GEXERAL COXFIGURATIO]^. 

Eastern Colorado lies on the western portion of the Great Plains, which extend 
from the foot of the Rocky Mountains to the Mississippi Valley. These plains 
present wide areas of tabular surfaces traversed by the broad, shallow valleys of 
large rivers that rise mainly in the Rocky ^lountains, and are more or less deeply 
cut by the narrower valleys of lateral drainage (PL II). Smooth surfaces and 
eastward-sloping plains are the characteristic features (PI. Ill), especially of the 
uplands, but in portions of the region there are buttes, extended escarpments, and 
canyons of considerable depth. Local areas of sand hills occur, especialh' along 
the rivers and on some of the high plains, where there is much loose material that 
can be blown hj the wind. The altitudes average about 6,000 feet at the foot of 
the mountains and about 3,500 feet along the eastern border of Colorado. Westward 
the mountains rise steeply to altitudes which reach over 14,000 feet in Pikes Peak, 
13,600 feet in Spanish Peaks, and 12,300 feet in Greenhorn Mountain. 

The principal streams of the region are South Platte and Arkansas rivers. 
These rise in the naountains, where they flow in deep canyons, but in crossing the 
plains their valleys are wide and average about 200 feet below the surrounding 
higher lands. Xear the mountains the Arkansas Valley is bordered in places by 
cliffs of moderate height, but to the east the side slopes are very gentle. The 
altitude in the valley at the mouth of Royal Gorge is 5,400 feet; at Pueblo it is 
4,675 feet, and at the Kansas line 3,350 feet. The average grade from Canyon to 
Pueblo is 15 feet to the mile, from Pueblo to La Junta, 8 feet, and from La Junta to 
the Kansas line, 7.3 feet. 

The principal branch of Arkansas River in southeastern Colorado is Purgatory 
River, which rises in the Culebra Range and empties at Las Animas. The region 
adjoining this stream is one of unusual topography for the Great Plains; portions 
of it consist of sandstone plateaus cut by many camions, that of Purgatory River 
being in places nearly 500 feet in depth. Other branches of the Arkansas crossing 
this plateau are Apishapa and Huerfano rivers, which have also cut canyons of con- 
siderable depth. Xear the southern margin of the State there rise above the plains 
two large, prominent mesas — the Raton Mesa and the Mesa de Maj-a — both of 
which are due to thick sheets of volcanic rocks. 




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U. S. GEOLOGICAL SURVEY 




A. THE HIGH PLAINS IN EASTERN COLORADO. 
Grass, sunshine, and solitude. 




£. VIEW ON THE GREAT PLAINS IN EASTERN COLORADO. 
Shows ranch situated in shallow drainage basin. 



• STRUCTURE. 9 

GENERAXi GEOIjOGY OF EASTERN COLORADO. 

GENERAL RELATIONS. 

The eastern half of Colorado is underlain by an extensive series of sedimentary 
formations of late Cambrian to Tertiary age. They are in widely extended sheets, 
which lie nearly level under the plains, but are upturned steeply against the front 
ranges of the Rocky Mountains, in which the underlying granites and gneisses 
appear. The larger surface areas are the later Cretaceous and Tertiary formations, 
the latter covering much of the region north. 

STRUCTURE. 

The general structure of the region is indicated in PI. XXVI, which shows the 
configuration of the "Dakota" sandstone, not only in its surface outcrops, but also 
under the areas in which it is more or less deeply buried by younger formations. 
From this illustration it will be seen that there is, along the mountain front, a 
general steep monoclinal dip, which affects all of the formations except the youngest. 

In greater part the monocline of the front ranges descends into deep basins, 
east of which the strata rise gently. The most extensive of these basins is one 
having its center near Denver. It extends from North Platte River to the Arkansas, 
and in its lower portion the granite and gneiss which are supposed to underlie 
the plains are 2,000 feet or more below sea level. This basin is terminated on the 
south by an anticline, which crosses the great offset and embayment in the moun- 
tain front west of Pueblo, and is a prolongation of the main Front Range of the 
Rocky Mountains. This anticline pitches downward very rapidly from a short 
distance south of Pikes Peak and crosses the Arkansas Valley a short distance west 
of Pueblo, beyond which it coalesces with a prominent anticline extending south- 
eastward from the Wet Mountain Range. Between these two, in the vicinity of 
Florence, there is a deep synclinal basin lying in the sharp reentrant angle in the 
front of the Rocky Mountains. South of the eastward prolongation of the Wet 
Mountain anticline there is another deep basin occupying an area of considerable 
extent about the Spanish Peaks. The east side of this basin rises into an anticline 
of moderate prominence, which occupies a broad area in southeastern Colorado, 
coalescing v/ith the extension of the Wet Mountain anticline to the northwest and 
extending far to the northeast, with considerable pitch, as the southeastern margin 
of the Denver basin. At Two Butte there is a small but prominent local uplift due 
to igneous intrusion. 

These flexures affect all of the formations except the later Tertiary sands, gravels, 
and clays which cap the divides between the larger valleys. In the Denver and 
Spanish Peaks basins there are extensive deposits of all the formations up to the 
earlier Tertiary. In the Florence basin a small area of the Laramie occurs. The 
anticlines north and south of Pueblo are exhibited mainly in "Dakota" to Niobrara 
formations, and the wide anticline in the southeastern portion of the State presents 
extensive exposures of the "Dakota" sandstone, which extend to Arkansas River 
between Las Animas and the vicinity of Lamar. 



10 ARKANSAS VALLEY IN EASTERN COLORADO. 

FORMATIONS. 

The sedimentary formations exposed in eastern Colorado represent a large 
part of geologic time from the later Cambrian to the present. Rocks of Silurian 
and Devonian age, however, are absent; the Ordovician and earlier Carboniferous 
appear onl}^ in small exposures; the Triassic may be absent in whole or in part; 
the earlier Jurassic is absent; the later Jurassic extends only a few miles into the 
northern portion of the State; a large part of the earlier Cretaceous is absent; and 
there are a number of short breaks in the early, middle, and latest Tertiary times. 

Rocks of later Cambrian age appear at a number of points along the Front 
Range, mainly in small embayments west and northwest of Colorado Springs and 
north of Canyon, but it is possible that these are projections from a more extended 
sheet which may underlie the plains eastward. It is evident that the Rocky 
Mountain Front Range was originally a shore line of irregular contour on which 
varying degrees of submergence caused an irregular seqiience of overlaps. The 
later Cambrian rocks are sandstones, evidently representing a shore deposit which 
originally had an irregular western margin, much of which is now buried under 
later overlapping sediments. 

The Ordovician rocks, which consist mainly of limestones (Manitou and Fre- 
mont), with an intervening local sandstone (Harding), are also of restricted occur- 
rence. Outcrops appear in Perrj'- Park, west and north of Colorado Springs, west 
and north of Canyon and Florence, south of Canyon, and southwest of Pueblo. 
At most localities they are overlain unconformably by the Millsap limestone, of 
earlier Carboniferous age, which presents irregular overlap relations from point to 
point. These formations probably extend continuously under the Great Plains, 
but they have not been reached by any borings in eastern Colorado. 

One of the most prominent members along the Rocky Mountain front is the 
great succession of "Red Beds" which lie on an irregular surface of the granites, 
except in some of the embayments where Canibrian, Ordovician, and earlier Car- 
boniferous rocks intervene. They have been found to be an extension of the 
"Red Beds" and underlying Carboniferous limestone of southeastern Wyoming 
and of the Permian and overling "Red Beds" of southern Kansas. They are 
readily divisible into three members. The lowest is the Fountain formation, or 
lower Wyoming. This consists of coarse, red grits, which I have found represent 
the Upper Carboniferous limestones of Wyoming. The second is the Tensleep 
sandstone, or "Creamy sandstone" of Eldridge, which has been traced as far south 
as the Manitou embayment. The third member consists of the gypsiferous red 
shales and sandstones know^n as the Chugwater formation, and is believed to rep- 
resent the "Red Beds" of eastern Wyoming and the Black Hills. The lower beds 
of this member are of Permian age and the upper beds are either Permian or 
Triassic. It appears to terminate a short distance southwest of Colorado Springs. 
The "Red Beds" underlie the plains in eastern Colorado and have been reached 
by several deep wells in the Arkansas Valley and b}^ some of the deeper canyons 
farther south. 

The marine Jurassic, which is well characterized in eastern Wyoming, extends 
only a short distance south into Colorado, where it thins out, but the unconformity 



U. S. GEOLOGICAL SURVEY 



PROFESSIONAL PAPER NO. 52 PL. IV 




A. HAYSTACK BUTTE, PUEBLO COUNTY, COLO. 
Typical flat-topped outline of Timpas limestone or Carlile shale. 




£. APISHAPA CANYON NORTHWEST OF THATCHER, COLO. 
Atypical sharp-edgeH flat-boltomed canyon in 'Dakota" sandstone. 



CRETACEOUS FORMATIONS. 11 

hj which it is separated from the "Red Beds" northward continues to the south, 
and represents, throughout the greater part of eastern Colorado, all of Jurassic 
and probabty also some of Triassic time. Above this unconformity lies a wide- 
spread sheet of fine-grained sediments Icnown as the Morrison formation, evidently 
of fresh-water origin and supposed to represent part of the earlier Cretaceous time. 
It is usually less than 300 feet thick, but appears to underlie all of eastern Colorado, 
although tliinning considerably eastward. 

The Morrison shales and clays are followed by a succession of coarse-grained 
sandstones, usually designated the "Dakota" sandstone, consisting of two prin- 
cipal masses with an intervening deposit of fire clay, having in all a tliickness 
averaging 300 feet. This series underlies all of the eastern part of Colorado, appear- 
ing prominently along the slopes of the Front Range and widely in the anticlinal 
uplifts south of Arkansas River. Its upper member undoubtedly represents the 
"Dakota" sandstone, but the medial clay and the lower sandstone series probably 
represent, respectively, the Fuson and Lakota formations, two Lower Cretaceous 
members of the Black Hills. The remarkable uniformity of this tripartite succes- 
sion and its intimate association with the underlying Morrison beds is a most 
significant feature over a wide area of the Rocky Mountain province. Several 
years ago fossils of Comanche age were found in the medial, or fire-cla}', member 
in the southeast corner of the State, and recently Mr. T. W. Stanton has obtained 
these fossils at this horizon at various localities as far west as Canyon. 

The " Dakota " sandstone is succeeded abruptly by a great succession of marine 
sediments, raainly shales, with limestones at certain horizons, representing a long 
interval of later Cretaceous time. The lower portion of this succession consists of 
the Benton group, which is from 400 to 500 feet thick in greater part and com- 
prises two shale formations separated b}^ one of limestone. Its character is con- 
stant throughout nearly a half million square miles of the central Great Plains. 
The rocks of the Benton group are exposed in a narrow zone all along the Rocky 
Mountain front and in extensive areas along the slopes of the anticlinal uplifts 
south of Arkansas River. They are succeeded by the calcareous deposits of the 
Niobrara, which attain their greatest development in eastern Colorado. The usual 
succession in the Niobrara is a lower limestone and an upper series of limy shale, 
which in portions of the Arkansas Valley attain a thickness of nearly a thousand 
feet. The Niobrara formation is extensively exposed in the Arkansas Vallej^ east 
of Florence. 

Overl;}'ing the Niobrara formation is a thick mass of claj' known as the Pierre 
shale, which has a wide extent and great thickness in the Denver basin, in the 
southern end of which it extends as far south as Arkansas River east of Pueblo. 
A smaller area occurs in the Spanish Peaks syncline, and a still smaller one in the 
Florence basin, where it is the source of petroleum. West of Denver the Pierre- 
formation appears to have a thickness of more than 7,500 feet; about Florence it 
is more than 3,000 feet thick; and in the Spanish Peaks sjmcline its greatest amount 
appears to be not more than 2,000 feet. The formation thins rapidly in eastern 
Colorado, where its surface has been extensively eroded in earlier Tertiary times. 
It consists of a succession of dark shales, with occasional beds of sandy shales 
and sandstones, and usually contains abundant remains of marine shells. 



12 ' AEKANSAS VALLET IN EASTERN COLORADO. 

The Pierre shale gives place rapidly to the Fox Hills formation, which in greater 
part consists of sandstones, and this, in turn, is succeeded b}^ the Laramie forma- 
tion, a thick succession of sandstones and sand}^ shales containing extensive and 
valuable deposits of lignite. The latter formation is of fresh-water origin and 
represents the product of late Cretaceous time. It occupies a broad area in the 
Denver basin, in which it extends southeastward from Colorado Springs and north- 
eastward into Wyoming and Nebraska. There is a large area of it in the Spanish 
Peaks basin and a small area in the Florence basin. 

In the two larger basins above mentioned the Laramie deposits are overlain 
by extensive beds, mainly of conglomerates and sandstones, which may possibly 
represent the earliest deposits of Tertiary time. Several formations separated by 
unconformities are comprised in this series, and they constitute the greater part of 
the elevated region culminating in the Spanish Peaks. 

There probably is a considerable interval of early and middle Tertiary time 
not represented by deposits in eastern Colorado. The White River group of Oligo- 
cene age caps the Laramie formation in the northeast corner of the State and 
occupies an area of considerable extent in the highlands south of Denver, where 
it is known as the Monument Creek formation. These Oligocene deposits consist 
of sands, sandstones, and clays, which probably were once of considerably 
greater extent in eastern Colorado, but were removed by later Tertiary erosion. 

On the principal divides in the eastern portion of Colorado there are wide 
areas of the original high" plains capped by later Tertiary deposits, consisting of 
sands and gravels, often locally cemented into a limestone grit. This formation has 
been extensively removed along the valleys of Platte and Arkansas rivers, but 
originally it probably extended to the foot of the higher mountain slopes, as it does 
in Wyoming. The . age of this covering of the old high plains is believed to be 
Pliocene, but in the northeastern portion of the State there is also an underlying 
member, the southern extension of the Arikaree formation, which lies on the White 
River formation for some distance. 

The Quaternary system in eastern Colorado is represented mainly by the 
alluvial deposits along the valleys and by some remnants of earlier terraces of 
moderate elevation. 

GEOLOGY OF THE ARKAISTSAS VALLEY REGIOIS^. 

STRATIGRAPHY. 

The sedimentary formations exposed in the area drained by Arkansas River 
in eastern Colorado are mainly of Cretaceous age, but along the slopes of the Rocky 
Mountains an extensive series of older formations lies on granite. The various 
formations of Cretaceous age present extensive exposures, but the older formations 
outcrop only in small areas, and there are among them many irregular overlap rela- 
tions, due to the unevenness of the surfaces on which they were laid down. The most 
extensive developments of the older"rocks are in the embayments north of Canyon 
and west of Colorado Springs. 



U. S. GEOLOGICAL SURVEY 



PROFESSIONAL PAPER NO. 62 PL. V 




A. "DAKOTA" HOGBACK AT CANYON, COLO. 
Valley of "Red Beds" and slopes of Morrison beds to left; minor hogbacks of Timpas limestone to right. Photograph by I. C. Russell. 





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ja,- 




B. "DAKOTA" HOGBACK RIDGE 2 MILES SOUTHWEST OF CANYON, COLO. 
Looking north. Valley of Graneros shale in foreground; mountains of gneiss in distance. Photograph by C. D. Walcott. 



STRATIGRAPHY. 

Table of geologic formations of southeastern Colorado. 



13 



Age. 


Formations. 


Principal character. 


Thickness. 






jSand, gravel, and loam 


Fett. 

60 


Quaternary 


[Higher terraces, sand, gravel, and loam. 






INussbaum-Ogalalla 


50 




Sand, gravel, and conglomerate. . 


150 


Tertiary 


j Monument Creek 


Sand, gravel, and clay 






200 




[Huerfano.. - 


Coarse sandstone and conglomerate on clays and 

marls. 
Massive sandstone; someday 


2,900 
475 




Cuchara (Denver) 


Cretaoeous( ?) 


Poison Canyon (Arapalioe) . . 
Laramie 


Sandstone conglomerate; some clay 






1,900 

2,000 

150 








Trinidad sandstone(FoxHills) 
Pierre 


Massive sandstone 




Dark-gray shale with concretions 


1,300-3,000 
650 
200 




Apishapa.. ^^ , 

_,. Niobrara group.. 

Timpas ^ '^ 

Carlile 

Greenhorn. l-Benton group 

Graneros. . 

"Dakota" 


j Sandy shale, thin beds of limestone- near top 

[Limestone and limy shale 




Dark shales with sandstone at top 


200 


Cretaceous 


iSlabby limestone; shale partings 






50 




Dark shales 


200 




Gray sandstone, fire clay in middle 


200- 300 




Comanche series 


Soft sandstone and sandy clays. . 


20 




Morrison 


Gray to maroon joint clays with limestone and 

sandstone layers. 
Bright-red sandy shales with thin limestone layers 

and gypsum; reddish sandstone at top. 

[Fine-grained massive sandstone 


200 


Triassio (?) and Permian. . 


Chugwater 


100 


Carboniferous: 


Tensleep, 1 

Fountain Lower Wyoming. . 
l(Badito) J 
Millsap 


200 


Pennsylvanian 


Coarse red sandstone and conglomerates. . . 






600-1,200 
30- 200 


Lower Mississippian 


Gray and purplish limestone 




rFremont 


Gray to pinkish dolomite, uneven grain 


100 




Harding 


Fine, even-grained, gray to pink sandstone; some 

shale. 
Reddish dolomite 


100 




Manitou 






100- 270 


Cambrian . - . 




Reddish sandstone 


40- 100 











CAMBRIAN SYSTEM. 

In the Manitou embayment west of Colorado Springs and in a small area north 
of Canyon rocks of Cambrian age appear lying on the granites. The deposits north 
of Canyon consist of a thin mass of sandy and cherty beds of variable local develop- 
ment at the base of the Manitou limestone. They have yielded a trilobite, Ptycko- 
paria, a form of Upper Cambrian age. In the Manitou embayment west and north- 
west of Colorado Springs the Manitou limestone is nearly everywhere underlain by 
10 to 80 feet of sandstones, mostly of pinkish color, containing Upper Cambrian 
fossils. Some of these were obtained by Doctor Cross from the east branch of Trout 
Creek, 45 feet above the granite; they comprised Lingulepis sp. (?) and a Lingula 
of elongate form allied to pinnxformis of the Upper Cambrian of Wisconsin. 

This sandstone appears at Manitou and extends northward along the west side 
of the Garden of the Gods to beyond Glen Eyrie, where it contains upper Cambrian 
fossils. One section which has been reported has, beginning at the base, 26 feet of 
greenish-white sandstone, 4 feet of coarse dark-green sandstone, 6 feet of coarse 



14 ARKANSAS VALLEY IN EASTERN COLORADO. 

gray sandstone, and 20 feet of brick-red sandstone with green layers, overlain by 
Ordovician limestone. A small area containing fossils was found southwest of 
Monument Park, and, according to Mr. W. T. Lee, a quartzite which is presumably 
of the same age appears on Deadman Creek south by west from Monument station. 

ORDOVICIAN SYSTEM. 

Rocks of Ordovician age are extensively exposed in the embayment north and 
northeast of Canyon and west of Colorado Springs, and two small areas have recently 
been observed southwest and south of Canyon. They consist of limestones and 
sandstones usualh" l}"ing on a thin deposit of Cambrian sandstone, or quartzite, and 
sometimes they overlap on the granite and schists. In the Canyon district the 
Ordovician is represented by the Manitou limestone, Harding sandstone, and Fremont 
limestone (PI. V, ^4). These have been described in detail by Dr. C. D. Walcott, " 
mainly in connection with the occurrence of fish remains, and by Dr. Whitman Cross 
in describing the region northeast of Canyon in the Pikes Peak folio. The following 
members are described by Doctor Cross : 

Manitou limestone. — This limestone is extensively exhibited in Oil Creek Valley, 
Garden Park, where it consists of fine-grained pink or reddish dolomite less than 
100 feet thick. It occurs in the Manitou region, where it contains OpJiileta, Game- 
rella, and other characteristic Ordovician fossils. 

Harding sandstone. — This formation consists mainly of fine, even-grained, granu- 
lar sandstone in alternating bands of light-gray and pinkish or variegated colors, 
with a few bands of dark-red or purplish sandy shale, having a maximum thickness 
of about 100 feet (Pis. VIII and XIX,). The lower part is sometimes calcareous 
and develops into a thin fine-grained dolomite. This formation contains fish remains 
at the Canyon locality. In Garden Park the sandstone rests with apparent conform- 
ity on the Manitou limestone, but to the southeast it overlaps on the basal sand- 
stone and near Canyon on the gneiss. At Canyon the formation is 86 feet thick 
and consists of gray, reddish, and purplish-brown sandstone and shales with many 
fossils of early Trenton age. A small outlier of sandstone, apparently of this forma- 
tion, underlying the Millsap (Carboniferous) limestones in the slopes west of Beulah, 
is mapped by Gilbert in the Pueblo folio. 

Fremont limestone. — Overlying "the Harding sandstone with apparent con- 
formity, there occurs a bluish-gray or pinkish dolomite of uneven grain, sometimes 
arenaceous, which gives rise to very rough weathered surfaces." Its thickness in 
Garden Park is about 100 feet, but increases southward to a maximum of 270 feet 
near Canyon, partly through the development of an upper fossiliferous member. 
In Garden Park it is characterized especially by the coral Halysites catenulatus, and 
also contains a molluscan fauna like that of the upper Trenton in New York. It 
appears to be restricted to a small area in Garden Park and vicinity and a narrow 
outcrop extending southward past Canyon. These formations all end a short 
distance southwest of Canyon by overlap of later deposits, but two small areas were 
found, one near the road 4 miles southwest of Canyon and another at the foot of the 
mountain on one of the branches of Chandler Creek, 7 miles nearly due south of 
Canyon, 

a Bull. Geol. Soc. America, vol. 3, pp. 153-167. 



pfiaPE&aioNf 



;. S GEOLOGICAL SURVEY^ 





SECTION I 



i. 






GEOLOGIC SECTION'S ACROSS SOUTHEASTERN COLORADO 

ALONG UNES 1,2,3 AND 4-,PL^-ES \T ANDXX\' 



L^mnupnnil 
Htm- Blinli! 



Slocriuin fbnnKtion 



N.H.DAHTOW 
1905 



f 



PALEOZOIC FORMATIONS. 



15 



At Manitou and for some distance northward and in the Trout Creek Valley 
(Manitou Park) there are other areas of Manitou limestone underlying the " Red 
Beds." On Trout Creek this limestone has yielded distinctive Ordovician fossils. 

Doctor Peale gives the following section of the exposure of Manitou limestone 
and associated formations at Glen Eyrie:" 

Geologic section of hasal roclcs near Glen Eyri^ Colo. 



Age. 



Carboniferous (?) . 



Ordovician. 



Description. 



Cambrian. 



Gray, purplish, and yellow limestones 

Red shaly limestones, with fragments ol Ordovician fossils 

Limestones with interlaminated shales -. . 

Red limestone with flint nodules 

Red limestone 

Red shaly limestone 

Red limestone 

Irregularly laminated limestone 

Red and greenish limestone 

Brick-red sandstone with green layers 

Coarse gray sandstone 

Coarse dark-green sandstone 

Coarse grayish-white sandstone 

Granite. 



Thick- 
ness. 



Feet. 
279 
4 
7 
7 
2 
1 
1 
3 
5 

20 
6 
4 

20 



On Deadman Creek, 6 miles south of Perry Park, a small outlying area has been 
investigated by Mr. Willis T. Lee.** The rocks are cherty limestones in layers inter- 
stratified with red clay, overlying a few feet of deep-red quartzite of supposed Cam- 
brian age. The fossils obtained were examined by Doctor Weller, who found the 
best preserved specimens to be Dalmanella testudinaria of Ordovician age. 

CARBONIFEROUS AND TRIASSIC SYSTEMS. 

Millsap limestone. — This limestone of Lower Carboniferous age appears in a 
few isolated outcrops west of north of Canyon and west of Colorado Springs. North 
of Canyon it lies on the Fremont limestone and is immediately overlain by the 
" Red Beds " of the Fountain formation. The locality in which the largest amount 
is exposed is in the angle between Oil and Millsap creeks, where there are about 
30 feet of thinly bedded, variegated, dolomitic limestones, with a few thin sand- 
stone layers. Chert nodules in the upper limestones carry casts of Spirifera rocky- 
montana and Athyris suUilita. The limestone appears at several points among 
the outcrops on the slope of the mountain northwest of Canyon. In the limestone 
area west of Colorado Springs, fossils of Carboniferous age have been discovered 
by Prof. A. W. Grabau. In a letter Professor Grabau states that they are remains 
of Spirifer, either rockymontana or centronatus, and small producti. They occur 
in a light-gray, compact limestone about 10 feet thick, lying from 10 to 15 feet 
below reddish and purplish shaly beds at the base of the Fountain formation. 
About 100 feet lower some other remains were found which were not determined. 



a Peale, A. C, Geology of the South Park division: Seventh Ann. Rept. U. S. Geol. and Geog. Surv. Terr., 1874, p. 201 
b Lee, W. T., Geology of the Castle Rock region, Colorado: Am. Geologist, vol. 29, pp. 96-97. 



16 ARKANSAS VALLEY IN EASTERN COLORADO. 

A small area of this limestone appears on the slopes west of Beulah, as described 
by Mr. Gilbert. In this locality its thickness is 200 feet and it consists of gray 
and purplish limestone with some shale in its lower part. Spirifera rocJcymontana 
occurs near its middle. It lies on supposed Harding sandstone, the Fremont 
limestone apparently being absent. 

The "Red Beds." — The most conspicuous sedimentary formations exposed 
along the Rocky Mountain Front Range is the succession of red sandstones known 
as the "Red Beds." For the greater part of their course they lie directly on the 
granite, but in the embayment about Manitou and Canyon they are locally under- 
lain by limestones. Near the Arkansas divide, at Palmer Lake, they are over- 
lapped by Monument Creek beds; west of Monument, southwest of Colorado 
Springs, and south of Canyon, they are faulted down, and southwest of Pueblo 
they are locally overlapped by the Dakota and associated formations. The thick- 
ness of the "Red Beds" is variable, but it is rarely less than 1,000 feet, and in the 
Garden of the Gods it is greater. Part- of the variation is due to the uneven floor, 
the thicker masses of the beds lying in the deeper depressions. The "Red Beds" 
are also exposed extensively in the Purgatory and other deep canyons in the High 
Plains south of Arkansas River. The rocks are mainly coarse-grained red grits 
and red sandstones. 

In the Manitou embayment there are three divisions of the "Red Beds." 
The uppermost consists of about 100 feet of red shales, *& thick bed of gypsum, 
and thin beds of limestone, and is believed to represent the Chugwater formation 
of eastern Wyoming (upper Wyoming beds). The medial member consists of about 
200 feet of fine-grained, light-colored, massive sandstone, which in the Boulder 
region has been designated the Lyons sandstone by Professor Fenneman." The 
lowest formation, the Fountain, is about 1,000 feet thick and consists of coarse 
red grits. In southeastern Colorado the upper part of the "Red Beds" consists 
of gypsum and red shales, which may represent the Chugwater (Lykens) formation ; 
as yet, however, no evidence has been found on which to base correlation. 

The "Red Beds" are extensively exposed in the Garden of the Gods and for 
some distance north and south, dipping nearly vertical. At the south they are 
cut off by the great fault which passes along the base of Cheyenne Mountain. They 
give rise to the picturesque features of the Garden of. the Gods, the Gateway 
marking the outcrop of the uppermost hard red stratum. Next above these are 
some softer striped red sandstones, about 100 feet thick, not well exposed at the 
Gateway, and then the white sandstone which outcrops a short distance east of 
the Gateway. This last bed is about 100 feet thick, moderately fine grained, mas- 
sive, and cross-bedded, and represents the "Creamy sandstone" of Eldridge (or 
the Lyons sandstone of Fenneman) , at the top of the lower Wyoming. The occur- 
rence of this lighter colored, finer grained sandstone at this horizon is general along 
the foothills of the Rocky Mountains from Manitou north, and in the Laramie 
Range, Black Hills, and Bighorn Mountains, being the Tensleep sandstone of the 
Bighorn slopes. Near the Garden of the Gods it is similarly succeeded abruptly 
by soft, red shales, including near the base thin limestones believed to represent 
the Minnekahta limestone and gypsum deposits above, and extending to typical 

oBull. U. S. Geol. Survey No. 265, 1905. 



U. S. GEOLOGICAL SURVEY 



PROFESSIONAL PAPER NO. 62 PL. VIII 




A. QUARRY IN HARDING SANDSTONE ON EAST SLOPE OF MOUNTAINS 2>: MILES NORTHWEST OF CANYON, COLO. 

Looking north Granite to left, Harding sandstone in quarry, Fiennont linnestone and "Red Beds" in slopes to right. Photograph by 

C. D. Walcott. 




B. FREMONT LIMESTONE NORTHWEST OF CANYON, COLO. 
Shows irregular erosion forms. 



RED BEDS. 17 

Morrison shale. This vipper series of red shales, limestones, and gypsiun 
undoubtedly is equivalent to the upper Wyoming of Eldridge (or L3dcens forma- 
tion of Fenneman). At its base, overlying the white sandstone, are 55 feet of soft, 
red shale and red clayey sandstone (Cpeche horizon), 25 feet of thin limestone 
la3^ers with red shale intercalations (Minnekahta), and 30 feet of red shales sur- 
mounted by a 30-foot bed of gypsum ovelain by Morrison shales. The following 
section was measured a short distance north of the Gateway to the Garden of 
the Gods: 

Section of the upper "Red Beds" hetween the Gateway of the Garden of the Gods and Glen Eyrie. 

Clays and shale (Morrison). 

Upper Wyoming beds: Feet. 

Gj'psum 30 

Red shales 30 

Limestone i r 3 

Red shales with thin limestones. . [(Minnekahta) < 22 

Purple limestone, thin layers J I 1 

Soft red shale and sandstone (Opeche) 55 

Top of lower Wyoming beds : 

Massive white sandstone (Lyons or Tensleep). 

To the south the "Red Beds," both upper and lower, preserve the same general 
features to the great fault at the foot of Cheyenne Mountain, though showing local 
variations. At the Gateway the 30-foot bed of gypsum is a conspicuous feature, 
and there is a thin bed of gypsum a short distance below its base. Just below the 
Gateway these beds are offset and twisted, so that they are locally deflected some 
distance west of the general line of strike. On the roadside south of the Gateway 
there are seen very coarse, cross-bedded materials in the upper part of the Fountain 
formation, giving place abruptly to the fine-grained red sandstones and red gypsif- 
erous shales of the upper Wyoming, all vertical or dipping steeply eastward, as 
shown in PI. IX, A. 

In the railroad cut in the western portion of Colorado City the following section 

is exposed: 

Partial section of "Red Beds" at Colorado City. 

Sandy shales, etc. (Morrison). Feet. 

Talus and " Red Beds " '. 50 

Impure gypsum 5 

Red shales and soft sandstone with 3 feet of thin beds of gj'psum near top 60 

Soft, massive, red sandstonje 55 

The section consists of upper Wyoming "Red Beds," except that the basal 
member may possibly be the upper part of the Lyons. 

When the "Red Beds" next appear, beyond the fault southwest of the village 
of Fountain, they are seen to consist, after the first 1 or 2 miles, almost entirely of 
coarse-grained materials without the uppermost gypsiferous red shales and to be 
overlain directly by Morrison beds. This coarse deposit, constituting the entire "Red 
Bed" section of this region, was designated the Fountain formation by Cross, a 
name which has been employed by Gilbert in the region still farther south. Here, as 
in the Manitou and Perry Park embayments, it is underlain by Millsap limestone. 

The Fountain formation in the region extending from southwest of Fountain 
to Canyon consists mainly of coarse-grained, crumbling, arkose sandstone in massive 

4551— No. 52—03 2 



18 



ARKANSAS VALLEY IN EASTERN COLOEADO. 



beds, usually cross-bedded. Many conglomeratic streaks occur and a basal con- 
glomerate often appears, notably on the road northwest of Canyon, where it lies on 
an eroded surface of Millsap limestone (PI. XX) . The beds are prominently reddish, 
but some are gray and others are mottled gray and red. Finer grained materials, 
nearly all of a bright brownish-red color, often occur. The thickness is estimated 
as 1,000 feet, but varies considerably. Nearly everywhere the formation is sepa- 
rated from the granites and gneisses by limestones of Ordovician age, but in places 
it overlaps the crystalline rocks, and at some localities the underlying limestones 
are faulted out. In the vicinity of Canyon and at a small locality on Cripple Creek 
at the head pf Garden Park the underlying Millsap limestone appears. In the region 
southwest of Pueblo the thickness of the Fountain formation, as measured by Mr. 
Gilbert, is 2,100 feet, including practically all of the formation, but it thins out to 
the southward and is absent for some distance along the foot of Greenhorn Mountain. 

At the south end of Greenhorn Mountain there appears a similar succession of 
rocks which Mr. Hills has named the Badito formation, probably corresponding 
to the Fountain formation. It comprises an upper member, about 100 feet thick, 
generally massive or thick-bedded, but sometimes shaly on the weathered surface, 
and a lower member, of about the same thickness, of very coarse brownish-red con- 
glomerate. Lying on granites and gneisses to the south this succession appears 
again in the Culebra Range, where it expands to a great thickness. The Carbonif- 
erous limestones appear again on this range about Veta Pass, and they extend 
southward into New Mexico. This area was described in considerable detail by 
Mr. Endlich, of the Hayden Survey, who mapped the lower portion of the series as 
''Lower Carboniferous," and several thousand feet of "Red Beds" as "Upper 
Carboniferous." 

In 1902 Mr. Willis T. Lee" collected fossils and made a section southwest of 
Spanish Peaks. These fossils, obtained mostly from the lower hundred feet of the 
formation, were identified by Dr. Stuart Weller and found to be Upper Carbonif- 
erous. The species were as follows: 



Zaphrentis sp. undet. 
Orbiculoidea convexa Shum. 
Orbiculoidea missouriensis Shum. 
Chonetes mesolobus N. and D. 
Productus longispinus Sow. 
Productus costatus Sow. 
Productus cora D'Orb. 
Spirifer cameratus Morton. 
Spirifer rockymontanus Marcou. 
Squamularia perplexa McCh. 
Seminula argentea Shep. 
Acanthopecten carboniferus Stev. 
Astartella concentrica McCh. 
Nucula ventricosa H. 
Lida bellistriata Stev. 
Pelecypod (genera and sp. undet.). 
Bellerophon percarinatus Con. 
Euphemus carbonarius Cox. 



Patellostium montfortianum N. and P.. 

Bellerophon sp. undet. 

RoteUa verrucelifera White. 

Soleniscus brevis White. 

Soleniscus sp. undet. 

Sphserodoma texana Shum. 

Sphserodoma sp. undet. 

Trachydomia wheeleri Swall. var. 

Naticopsis altonensis McCh. 

Naticopsis altonensis var. gigantea M. and W. 

Pleurotomaria perizomata White. 

Pleurotomaria (several species undet.). 

Murchisonia copei White. 

Orthoceras sp. undet. 

Syringopora sp. 

Campophyllum torquium Owen. 

Straparollus catilloides Con. 



o Carboniferous of Sangre de Cristo Range, Colorado: Jour. Geol., vol. 10, pp. 393-396. 



U. S. GEOLOGICAL SURVEY 



PROFESSIONAL PAPER NO. 62 PL. IX 




A. VERTICAL LOWER "RED BEDS," GARDEN OF THE GODS, COLORADO. 
The harder portions rise in pinnacled forms. 




B. THE STONEWALL ON PURGATORY RIVER 30 MILES WEST OF TRINIDAD, COLO. 
Looking southeast across valley of Benton and Pierre shale to ridge of overlying sandstones. 



UPPER CARBONIFEROUS FOSSILS. 19 



Other fossils, found in loose fragments, were as follows: 



Derbya crassa M. and H. 
Hustedia mormoni Marcou. 
Allorisma subcuneatuin M. and H. 
Sehizodus wlieeleri Swall. 



Belleroplion (large sp. imdet.). 
Temnocheilus winslowi M. and W. 
Phillipsia sp. 
Large fish spine. 



The following section is given by Mr. Lee: 

Section at the crest of the Culebra Range, between Middle Fork and North ForJc of Purgatory River. 

Feet. 

Hard quartzitic conglomerate 10 

Dark shale 5 

Limestone, fossiliferous 2 

Red sandstone, with bands of red shale and irregular masses of limestone 12 

Greenish argillaceous sandstone 4 

Pink sandstone, argillaceous above, conglomeratic below 18 

Fossiliferous limestone 4 

Deep-red sandstone, conglomeratic at the base, shaly near the top 10 

Limestone, arenaceous near the base , . . 20 

Massive, light-colored grit, coarse and conglomeratic 13 

Banded sandstone and limestone intimately commingled; the limestone is often in more or less rounded 

masses ; irregular beds of gravel occur in places 6 

Nodular limestone 3 

Massive limestone 8 

Shale with limestone nodules 3 

Massive limestone 23 

Coarse sandstone, conglomeratic in the lower half 20 

Massive grit (local unconformity) 8 

Calcareous shale, passing to black shale, with limestone nodules near the top 10 

Fossiliferous Hmestone with sandstone layers; cup corals abundant ■ 15 

Massive limestone 6 

Shale 8 

Coarse grit 2 

Sandstone with large nodules and irregular masses of Hmestone 10 

Shale with bands of sandstone and limestone 25 

Banded limestone 4^12 

Soft black shale, fossiliferous 28 

Coarse grit 9 

Black shale 6 

Coarse grit, conglomeratic in places 2-20 

Dark shale, with limestone nodules and thin seams of sandstone; runs to massive limestone in places; 

becomes red and arenaceous near the base 45 

Coarse grit 7 

Dark-red shale, with nodules and irregular masses of limestone 10 

Limestone 4 

Red to black micaceous shale, with bands of sandstone near the base, and limestone midules near the top. 12 

Coarse grit 10 

Red grit and conglomerate (?) 

Crystalline rocks of the mountains. 

A small collection of fossils was also obtained from the western slope of Veta 
Pass, 5 miles above Placer, in a succession consisting of sandstones, limestones. 



Hustedia mormoni Marcou. 
Aviculopecten occidentalis. 
Astartella concentrica McCh. 
Schizodus wheeleri, Swall. 
Bellerophon percarinatus Con. 
Bellerophon inspeciosus White? 
Soleniscus sp. 
Conularia? sp. 
Orthoceras sp. 



20 ARKANSAS VALLEY IN EASTERN COLORADO. 

shales, and conglomerates similar to those above described. The following Upper 
Carboniferous forms were found at this locality : 

Zaphrentis sp. 
Orbiculoidea sp. 
Derbya crassa M. and H. 
Chonetes granulifera Owen. 
Chonetes mesolobus N. and P. 
Productus nebrascensis Owen. 
Productus costatus Sow. 
Spirifer cameratus Morton. 
Squamularia perplexa McCh. 
Seminula argentea Shep. 

The Millsap and underlying limestones were not found by Mr. Lee in the Culebra 
Range, although possibly there may be small outliers of them in portions of the 
range which he did not visit. The strata overlying the section given above consist 
of several thousand feet of red and gray sandstones, mostly coarse, extendihg to 
the base of the Morrison and representing the Fountain formation. 

In the canyon of Cuchara River, near the north line of Huerfano County, the 
upper portion of the "Red Beds," here termed the Badito formation by R. C. Hills," 
is exposed. At Red Rocks, in the canyon of Purgatory River, in the northern portion 
of Las Animas County, there are extensive exposures of the "Red Beds" and an 
overl3ring bed of gypsum which appears to belong with them. Several hundred 
feet are exposed, consisting at the top, under the gypsum, of a coarse, conglomer- 
atic, massive, red sandstone, which merges downward into more regularly stratified 
red sandstones, with occasional layers of sandy red shales. In the uppermost sand- 
stone the writer found a small bone fragment, apparently a portion of a scapula of 
a bolodont, which would suggest that this member of the formation is of Triassic age. 

Partial section of "Red Beds" in Plum Canyon near Purgatory River, Las Animas County, Colo.b 

''Dakota" sandstone: Feet. 

Two massive sandstones, with clay between 140 

Morrison formation: 

Variegated shales, with thin limestone layers s. 85 

Dark shales, with irregular masses of gypsum 15 

Gypsum, with streaks of clay 1 J 

Variegated shale, with much gypsum in masses up to a foot in diameter 8 

Gypsum in layers sometimes separated by layers of clay 25 

Massive gypsum 5 

Red gypsiferous shales, soft and regularly bedded 30-40 

Red calcareous sandstone, oolitic, cross-bedded, layers variable in thickness and character, shaJy near 

top, grading into gypsiferous shales 60 

Red sandstone, massive, cross-bedded 175-200 

Red arenaceous shales 6 

Red sandstone 1 

Fine, red shale 4 

Even-bedded red sandstone , 9 

Red arenaceous shale 2 

Red sandstone, cross-bedded 40 



oHills, R. C, Description of the Walsenbuvg district: Geologic Atlas U. S., iolio 68, U. S. Geol. Survey, 1900. 
t> Lee, W. T., Morrison formation of Colorado: Jour. Geol.. vol. 9, 1901, p. 346. 



MORKISON FORMATION. 21 

Feet. 

Loose red sandstone, alternating with shale 15 

Massive red sandstone 5 

Soft red sandstone containing ripple-marked hard layere 30 

White, hard/ argillaceous limestone, thin layers, contorted 4 

Red sandstone to river bottom 15 

The correlation of these "Red Beds" with the Wyoming formation is reasonably- 
certain when their character and relations are considered, and apparently the upper 
gypsiferous series represents the upper Wyoming. They underlie a wide area in 
southeastern Colorado and have been penetrated by some of the wells. The well at 
La Junta reached them at 605 feet and continued in them to 1,150 feet. The well 
at Bloom penetrated them from 400 feet to 1,162 feet without reaching their bottom. 
They also appear in some of the deep canyons south of the west end of Mesa de 
Maya, but their character in that region was not ascertained. 

The "Red Beds" are exposed over an area of about 3 square miles in the Two 
Butte uplift on Two Butte Creek in Prowers and Baca counties. They are described 
by G. K. Gilbert, " who estimates that over 600 feet are exhibited. The lowest 
beds are sandstones and shales, the latter predominating somewhat. Some of the 
beds are orange or yellowish. These are overlain by white limestone 5 to 10 feet 
thick, which was found to be very like the Minnekahta limestone in thin-bedded char- 
acter and general aspect in the outcrops. This limestone is overlain by brick-red 
shales about 150 feet thick, becoming sandy at the top and merging into a massive 
red sandstone over 300 feet thick, which forms prominent bluffs along the creek and 
caps the butte, which was uplifted by the laccolithic intrusion of the igneous rock. 
At one place this sandstone is parted by 40 to 50 feet of shale. Parts of the sand- 
stone are buff, yellow, or gray, and somewhat resemble the "Dakota" sandstone, 
for which it has been mistaken here and elsewhere. It is, however, separated from 
the "Dakota" and probably represents the Exeter sandstone of Mr. Willis T. Lee, 
which appears to the south along Cimarron River. 

CRETACEOUS SYSTEM. 

Morrison formation. — This formation extends along the base of the Rocky 
Mountains, where it outcrops frequently and presents very characteristic features. 
In a few localities, as along the foot of Cheyenne Mountain and south of Canyon, 
it is cut off by faults and for short distances it is overlapped by younger formations. 
It is also exposed in sonie of the canyons eastward, notably in the deeper ones of 
eastern Las Animas County. Its general character is nearly uniform throughout, 
consisting of light-colored massive clays, or "joint clays," with thin beds of lime- 
stone and sandstone of, fresh-water origin, containing bones of saurians of the 
so-called " Atlantosaurus fauna." Its thickness averages less than 200 feet in 
most cases. It presents frequent and rapid variations in the local succession of 
beds, but the preponderance of "joint clays" of chalky aspect and the occurrence 
of maroon ^nd purplish layers among them are characteristic features. The name 
Morrison was given by Eldridge, from the town of Morrison, where the formation 
is extensively developed. The Morrison beds lie unconformably on the Chugwater 

o Gilbert, U. K., Laccoliths in southeastern Colorado: Jour. Geol., vol. 4, 1896, pp. 816-825. 



22 ARKANSAS VALLEY IN EASTERN COLORADO. 

or gypsiferous "Ked Beds" for many miles, and, southwest of Colorado Springs, 
overlap onto the " Red Beds" of the Fountain and Badito formations. In eastern 
Las Animas County they lie on a bed of gypsum. From the saurian remains which 
have been obtained so abundantly from the Morrison beds west of Denver and north 
of Canyon, the formation is regarded as latest Jurassic by some paleontologists and 
as earliest Cretaceous by others, but from its close connection with the overlying 
sandstone, the writer considers it preferable to class it as Cretaceous. 

The formation is well exposed a short distance north of the Gateway to the Garden 
of the Gods, where its thickness is 130 feet. The basal beds here lie on the thick 
deposit of gypsum at the top of the Chugwater formation and consist of ash- 
gray, massive shales with several thin limestone layers and a few streaks of shales 
with clay pebbles. These grade up into typical pale, greenish-graj^ and maroon, 
massive clays with a few thin layers of fine-grained, light-colored sandstone 
abruptly • overlain by coarse-grained, buff-colored "Dakota" sandstone. At 
Colorado City the Morrison beds are exposed only in part in the railroad cut, the 
top and bottom members being covered by talus. The beds stand nearly or quite 
vertical. To the west are 55 feet of pale greenish-gray, sandy shale, mostly massive, 
with thin layers which are overlain (to the east) by a 15-foot bed of soft, pale greenish- 
gray sandstone. The formation is cut ofl' by the fault south of Colorado City, but 
reappears in the embayment north and northeast of Canj^on. In Garden Park, 
on Oil Creek, it has a thickness of about 350 feet, according to Cross, °- and consists 
mainly of greenish, pinkish, or gray shales or marls with sandstone layers at various 
horizons. It usually lies on the Fountain formation, but overlaps locally onto the 
granite. In this region the formation has yielded large numbers of dinosaur repiains. 

Hatcher ** has described the Morrison formation and its relations in the Garden 
Park area and given some details regarding the fossiliferous horizons. He esti- 
mated the thickness at 450 feet, placing the upper limit higher than Cross did, so 
as to include the highest sandstones and shales containing dinosaur remains. 
The bones have been obtained in largest number from a thick sandstone layer about 
150 feet above the base of the formation shown in PI. X, B, but some occur 
30 feet below this stratum and others have been found at various horizons above, 
both in shale and in sandstones. Just below the main bone-bearing sandstone bed 
there is a layer of clay with thin limestone beds containing numerous fresh-water 
gasteropods, and at a somewhat lower horizon, a marly layer with abundant remains 
of unios. These shell fossils have been described by C. A. White, who classes them 
as Jurassic because they occur with supposed Jurassic dinosaurs, but states that 
otherwise they might be much younger, so that they throw no light on the age of 
the beds. The late J. B. Hatcher found an Inoceramus at the Garden Park locality. 

Near Canyon there are excellent exposures of Morrison formation on the west 
slope of the "hogback." At the top are alternating sandstones and shales, 150 feet 
thick, lying on purple and green shales 160 feet thick, at the base of which there is 
a prominent layer of limestone 4 feet thick, which contains many fresh-water shells. 
Below this are 40 feet of pale bluish-green massive shales lying on sandstones. The 

o Cross, Whitman, Description ol the Pikes Peak district: Geologic Atlas U. S., folio 7, U. S. Geol. Survey, 1894, p. 2. 
6 Hatcher, J. B., Annals Carnegie Museum, vol. 1, 1901, pp. 327-341. 



U. S. GCOLOGICAL SURVEY 



PROFESSIONAL PAPER NO. 52 PL. X 








.^■^ 






ij: ^.r*'^ >> 



v-^.-.- >^ 




A. DAKOTA SANDSTONE IN HOGBACK RIDGE 2 MILES SOUTHWEST 
OF CANYON, COLO. 

Looking north. Shows upper and lower sandstone members with intermediate shales. 




B. BONE-BEARING SANDSTONE IN MIDDLE OF MORRISON FORMATION IN GARDEN PARK NORTH OF CANYON, COLO. 

Photograph by I. C. Russell. 



MORRISON FORMATION. 23 

total thickness appears to be nearly 400 feet. Four miles south of Canyon the 
formation lies directly on granite, as shown in PI. XVII, B, and described on page 42. 

Six miles south of Canyon the Morrison beds are faulted out, or overlapped by 
j-ounger strata, and do not reappear until in the vicinity of Mineral Creek south of 
Florence, whence they extend southward into North Creek Valley. According to 
Mr. G. K. Gilbert, the "Dakota" sandstone lies directly on the Fountain formation 
north of Beulah for several miles, but probably the Morrison beds formerly covered 
the region and were removed by pre-" Dakota" erosion. The Morrison beds appear 
south of Beulah, where, as described by Mr. Gilbert," they consist chiefly of red 
shale with a few layers of hard, red sandstone beds about 70 feet thick. They are 
faulted against the gneiss and also overlap onto that rock for a portion of their 
course; near the contact they are paler in color, white and orange predomi- 
nating, and no reds appear. The formation comes up again for 5 miles at the south 
end of Greenhorn Mountains, lying partly on gneiss and partly on the "Red Beds." 
Its thickness here, according to Hills,'' is 270 feet, the lower portion consisting of 
about 60 feet of soft white sandstone, conglomeratic at base. The middle portion 
is a series of pinkish and greenish massive clays, and the upper beds are variegated 
shales and clays, alternating wdth bands of fine-grained limestone often containing 
vermilion-colored cherts. Hills states that there is considerable doubt as to the 
true position of the formation in the time scale, but assigns it provisionally to the 
Jurassic. 

Mr. Willis T. Lee has made a special study of the Morrison formation in the 
southern Colorado region,'^ and his work has thrown much light on its distribution 
and components. He describes its continuation southward along the foot of the 
Rocky Mountains west of the Spanish Peaks into New Mexico and its existence in 
the deep canyons of Las Animas County, Colo., and southward. He has found 
that it presents its usual characteristics, regular stratigraphic position and dinosaur 
remains. The first exposures east of the foot of the mountains are in Cuchara and 
Huerfano canyons in western Huerfano and southern Pueblo counties, where Hills 
reports the formation as 100 feet thick and consisting of variegated shales and clays 
alternating with layers of fine-grained limestone. In Apishapa Canyon north of 
Thatcher the typical Morrison is reported by Lee, underlying the "Dakota" sand- 
stone. There are extensive exposures in Purgatory and adjacent canyons where 
the "Red Beds" are uplifted. Mr. Lee gives the following section, in Plum Canyon 
near its mouth: 

Geologic section of Morrison formation in Plum Canyon, Las Animas County, Colo. 

''Dakota": Feet. 

Massive sandstones * 140 

Morrison : 

Greenish clay and shale, soft and fine grained 11 

Dull red clay, soft and fine grained 12 

Brown to yellow shale 10 

Argillaceous limestone, fine, dark laminse \ 

a Gilbert, G. K., Description of the Puelilo quadrangle: Geologic Atlas U. S., folio 36, U. S. Geol. Survey, 1897. 
b Hills, R. C, Description of the Walsenburg district: Geologic Atlas U. S., folio 68, U. S. Geol. Survey, 1900. 
cLee, Willis T., Jour. Geol., vol. 9, pp. 343-352; vol. 10, pp. 36-58. 



24 ARKANSAS VALLEY IN EASTERN COLORADO. 

Morrison — Continued. * Feet. 

Buff-colored shale - li 

Argillaceous limestone, fine, dark lamin* J 

Variegated joint clay 18 

Argillaceous limestone, fine grained and hard with contorted laminse 2 

Variegated shales, very soft 30 

"Red Beds"?: 

Dark shale and gypsum on Red Beds. 

Lee gives the following section in Red Rock Canyon, a small side canyon of 
Purgatory River: 



Geologic section of Morrison beds in Red RocTc Canyon, Las Animas County, Colo. 

"Dakota:" Feet. 

Massive sandstone . . . _ 

Morrison : 

Brick-red sandy shale, with bands of hard, fine-grained sandstone 25 

Reddish limestone, conohoidal fracture 3-5 

Soft, dark, clay shale 30 

Light-brown clay shale 11 

Argillaceous limestone ^ J 

Brown shale 7 

Concretionary limestone 1 

Variegated joint clay 7 

Yellow paper shale 3 

Argillaceous limestone, thin layers \ 

Fine shale \\ 

White limestone 1 

Variegated clay shale 15 

Argillaceous limestone, thin layers f 

Yellow shale 4 

Sandstone with agate masses 1 

Soft, thin-bedded sandstone S 

Soft massive sandstone * 2 

Paper shale. 2 

Soft massive sandstone 7 

"Red Beds:" 

Gypsum and clay on red sandstone 12-20 

In this canyon the thickness is 132 feet;- in Chaquaqua Canyon, 10 miles from 
the mouth of Plum Canyon, it is 175 feet (by barometer), and the predominating 
material is a variegated clay shale popularly termed ' 'joint clay." Lee says: 

A subordinate amount of sandstone occurs in places, but there seems to be no particular horizon at which 
this is likely to be found. In Red Rocks Canyon it occurs at the base; in Plum Canyon none is found; in a 
side gulch east of Plum Canyon a brecciated layer occurs near the top containing angular fragments one-fourth 
inch in diameter; in Chaquaqua Canyon, 4 miles from the mouth of Plum Creek, a coarse, cross-bedded sand- 
stone layer 15 feet in thickness occurs about 50 feet from the top; just across the canyon from this point, 
perhaps 2 miles distant and at the same horizon, about 30 feet of limestone is found in place of the sandstone- 
In many places the sandstones are friable and composed of nearly pure quartz. * * * The occurrence 
of the limestones, most of which are more or less argillaceous, is as erratic as that of the sandstones. The 
relative amount and position of sandstone, shale, and limestone vary locally. 

Dinosaur bones were observed by Mr. Lee in the shales at nearlj^ every horizon, 
but no invertebrates were found. It is reported that the formation is sharply sepa- 
rated from adjoining formations, but without evidence of unconformity by erosion. 



U. S. GEOLOGICAL SURVEY 



PROFESSIONAL PAPER NO. 52 PL. XI 





THE STONEWALL ON PURGATORY RIVER WEST OF TRINIDAD, COLO.; A MONOCLINAL 
RIDGE OF "DAKOTA" SANDSTONE. 



A. Looking west to Culebra Range. B. Looking south, showing red valley to right and valleys of Graneros 

and overlying shales to left. 



COMANCHE AND "DAKOTA BEDS. 25 

The gypsiferous shales appear to be distinct, and are regarded as a portion of the 
"Red Beds." The formation extends down Purgatory River to the west hne of 
Bent County, where it passes beneath the "Dakota" sandstone. In Muddy Creek 
Valley, in the southern corner of Bent County and the adjoining portion of Las 
Animas County, the Morrison formation is bared of "Dakota" sandstone over an 
area of several square miles in which the same general features are presented as in 
Purgatory Valley. It again appears in Longs Canyon, and the writer found it 
apparently exposed in the Two Butte uplift on Two Butte Creek, where it is thin, 
but consists of gray aiid purplish clays with layers of light-colored sandstones and 
limestones overlying buff and red sandstones at the top of the " Red Beds." In a 
paper presented to the Geological Society of America, in December, 1902, Mr. Willis 
T. Lee announced that he had traced the formation eastward down the Cimarron 
Valley into Oklahoma. 

Comanche series. — This series was first discovered'^ in Colorado on Two Butte 
Creek, 5 miles east of Two Butte, and during the summer of 1905 Mr. T. W. Stanton 
and Mr. Willis T. Lee found Comanche fossils in the fire clay lying between the two 
sandstones of the " Dakota" in Purgatory Canyon south of La Junta, while later Mr. 
Stanton found them in the same position west of Canyon. This important discovery 
indicates a wide extension of the formation to and along the Rocky Mountain Front 
Range, constituting the middle and lower portions of the "Dakota" formation. 
At the Two Butte Creek locality the creek crosses a low anticline in which the 
upper member of the " Dakota" sandstone is seen to be underlain by 20 feet or more 
of sandy shales containing numerous GrypTisea corrugata Say, a fossil characteristic 
of the upper part of the Comanche series. The locality is just above Mechling's 
ranch, in bluffs along the south bank of the creek. Doubtless the Comanche beds 
underlie the greater part of Baca County, for they have been discovered by Mr. 
Willis T. Lee along the Cimarron near the New^ Mexico-Oklahoma line. Possibly 
they are exposed along Bear and Horse creeks, but these streams have not been 
especially examined for outcrops of beds underlying the top " Dakota" sandstone. 

" Dakota " sandstone. ^-TJnder this heading will be described the entire sandstone 
succession overlying the Morrison formation, for this always has been known as the 
" Dakota" sandstone or " Dakota" formation. It generally consists of two bodies of 
sandstone, each a hundred feet or more in thickness, separated by a deposit of clay or 
shale from 10 to 15 feet thick. This clay in the Golden region and the top sand- 
stone at various localities have yielded abundant plant remains of the Dakota 
flora (Upper Cretaceous). The tripartite succession strongl}^ suggests the Dakota 
sandstone, Fuson clay, and Dakota sandstone of the Black Hills, and the Lower 
Cretaceous age of the two latter, at least in southeastern Colorado, is proved by the 
occurrence of Comanche fossils in the fire-clay member, as described in a preceding 
paragraph. 

The "Dakota" sandstone is remarkably imiform in character throughout 
eastern Colorado. The sandstones are mostly hard and .massive, giving rise to a 
well-marked hogback range along the foothills (Pis. V and IX, B) and plateaus, with 
steep-walled canyons in the southeastern part of the State (PL IV, B). The pre- 
dominating color is light buff, but some portions are light gray or white, and 

a Decsribed by N. H. Darton, in Science, vol. 22, p. 120, 1905. 



26 ARKANSAS VALLEY IN EA.ST:ERN COLORADO. 

darker tints are not infrequent, especially in the upper beds. Cross-bedding is 
almost general and conglomeratic streaks are frequent, especially at or near the base 
of the lower sandstone. The contact with Morrison beds is abrupt and often presents 
evidence of slight unconformity b)^ erosion. There is often a rapid change to Benton 
deposits, but in most areas there are a few feet of transition beds consisting of an 
alternation of shales with thin-bedded brown sandstones. The lower sandstone 
member is thicker than the upper, often somewhat softer, and it contains shale 
partings at some localities. The middle shale member appears to be present through- 
out, but generally it is covered by talus. It is well shown in PI. X, A. In the 
Garden of the Gods region Doctor Peale reports a thickness of 257 feet, consisting 
of 200 feet of massive sandstones above, underlain by a finer-grained sandstone, 
in part yellow, containing fragments of Lingula and a lignitic layer with vegetal 
fragments. The writer's measurement in vertical beds near the Gateway gave 
considerably less thickness, and the formation was found to consist of two massive 
beds of sandstone, apparently with a thin series of shales between. The great 
fault cuts ofT the formation southwest of Colorado Springs, but it appears again in 
.the region of Canyon, where Cross describes it as having a thickness of 300 feet and 
as consisting mainly of pure white or gray sandstone, usually friable, of uniform 
texture, with a thin basal conglomerate. Dark shale layers are reported midway in 
the formation in which, in the summer of 1905, T. W. Stanton found Comanche 
fossils. Fossil leaves are said to occur in thin layers at various horizons. 

"Dakota" sandstone is prominent at the foot of Wet Mountains southwest of 
Pueblo, as described by j\Ir. Gilbert. "^ Its greatest measured thickness is 650 feet, 
near Beulah, where it consists almost entirely of sandstone; elsewhere in the area it 
contains beds of shale and is 300 to 350 feet thick. The basal portion usually is 
conglomeratic, sharply separated from the Morrison clays and the Fountain forma- 
tion, which it overlaps locally. At the top there is a transition into the Benton 
(Graneros) shales, through an alternation of shale and tliin-bedded, brown sand- 
stones. 

In the northern portion of Huerfano County and along the foot of Greenhorn 
Mountain the formation is described by Hills as consisting of 350 feet or more of 
sandstone, of which the lower two-thirds consists generally of a yellowish-gray rock 
of coarse, porous texture, with some layers of fine conglomerate, commonly cross- 
bedded. This lower member is separated from the upper one by gray shales 8 to 10 
feet in thickness. The upper sandstones aggregate 100 to 150 feet in thickness, are 
light gray, and of fresh, fine-grained, close texture, regularly bedded. The formation 
lies in part on the Morrison, but in places along the mountain front overlaps the 
granites and schists. In the canyons of Cuchara and Huerfano rivers it lies nearly 
level and presents steep canyon walls surmounting slopes of Morrison clay. The 
"Dakota" sandstone is a prominent feature in the foothills extending between 
Spanish Peaks and the Sangre de Cristo Range, appearing for many miles as a vertical 
"stone wall" rising high above the adjoining softer beds. 

In the extensive exposures of "Dakota" sandstone in the eastern half of Las 
Animas County is presented a regular succession of the two massive sandstone layers 
with their intervening shales or fire clay containing Comanche fossils. Referring 



a Gilbert, G. K., Description of the Pueblo quadrangle: Geologic Atlas U. S., folio 36, U. S. Geol. Survey, 1897, p. 6. 



U. S. GEOLOGICAL SURVEY 



PROFESSIONAL PAPER NO. 52 PL. XII 




A. GREENHORN LIMESTONE NEAR THATCHER. COLO. 
Typical view showing limestone with interbedded black shales. Base of this formation is about 200 feet above water-bearing Dakota sandstone. 





£. TIMPAS LIMESTONE IN QUARRY SOUTHEAST OF LA JUNTA, COLO. 
Shows thickness of beds and inteicalations of shale. 



GEANEKOS AND GEEENHORN BEDS. 27 

to the formation in Purgatory Canyon, near longitude 104°, Hills states that the 
thickness is about 375 feet, and that the lower two-thirds consists of massive, mostly 
cross-bedded sandstones, with a few shale partings between the beds and more or 
less fine conglomerate. This basal member is overlain by a layer of fire clay, the 
position of which is marked by a narrow shelf due to the projection of the under- 
lying sandstone. The upper sandstone is grayish M^hite, thinner bedded, with more 
numerous shale partings and generally finer grain and more compact than the lower, 
more porous sandstone. These features prevail over the wide area of "Dakota" 
outcrop in southeastern Colorado, in Baca, Prowers, and Bent counties, but with 
many variations of thickness and local details of stratigraphy. In the vicinity of 
the Two Butte uplift the sandstone has been extensively eroded over an area about 
a mile square. The buttes are capped by a thick, massive sandstone (Exeter?), 
which is the upper member of the " Red Beds" and is separated from the "Dakota" 
sandstone by supposed Morrison shales and limestones. 

Graneros shale. — This shale, which is the basal member of the Benton group, 
underlies a large portion of eastern Colorado. It outcrops in a narrow zone along 
the foothills of the Rocky Mountains and in broader areas on the flanks of the anti- 
clines in Pueblo, Huerfano, and Las Animas counties, and along the Arkansas 
Valley east of La Junta. Its thickness generally averages 200 feet, and it appears 
to be perfectly conformable to the adjoining formations. Usually there are a few 
feet of transition beds to the "Dakota" sandstone at its base and to the overlying 
Greenhorn limestone. The shale is mostly hard and fissile; its color is bluish gray, 
darkest in the middle and slightly lighter in the upper and lower beds. Thin beds 
of white clay occur locally. In the region south of Pueblo the formation contains 
a layer of limy sandstone 1 to 2 inches thick about 50 feet below the top of the 
formation. It contains fossil shells of several species. Concretions of carbonate of 
lime occur at various levels in most localities, especially 20 to 30 feet above the base 
of the formation. In some districts this horizon of concretions changes into a layer 
of dark-gray limestone, 8 inches to a foot in thickness, which weathers to a bright- 
orange color. In general the formation appears in gentle slopes of gray clay, with 
occasional concretions, and in some recently cut banks the shaly character of the 
less weathered material is apparent. In most of the Arkansas Valley region the 
thickness varies only from 200 to 210 feet, but north of Canyon it is between 325 and 
350 feet, and 3 miles south of that city it is 250 feet. The limestone layer occurring 
30 feet above the base of the formation is most conspicuous in the region east and 
northeast of Trinidad, where its thickness is 1 to 2 feet. It is hard and of concre- 
tionary structure. It weathers to a bright-orange color, so that it is a conspicuous 
feature. 

Greenhorn limestone. — This medial formation of the Benton group outcrops 
along the margin of the Graneros shale area above described. Its thickness varies 
from 30 to 50 feet. It consists of beds of pale bluish-gray, fine-grained, compact 
limestone, mostly 3 to 10 inches thick, separated by dark-gray shales 4 to 18 inches 
thick. (PI. XII, A.) These intermediate shale beds are usually thicker where the 
formation is thickest. The limestone has a strong tendency to split with vertical 
cleavage into small slabs one-fourth inch to 2 inches in thickness, which form a con- 
spicuous feature on the slopes. At most localities the formation grades into the 



28 AEKANSAS VALLEY IN EASTERN COLORADO. 

adjoining formations through a few inches of passage beds. A few thin beds of 
white clay have been reported as occurring in the formation at points in the vicinity 
of Pueblo. Most of the limestone beds contain an abundance of a hig-hly characteris- 
tic fossil, Inoceramus labiatus. This form is represented by casts and impressions 
often closely packed together in some of the layers. The appearance of this fossil 
is shown in PI. XIII, B. It is not known to occur in any of the formations. In 
the shales between the limestone layers a somewhat similar fossil occurs, often in 
considerable abundance. In most districts the ledges of Greenhorn limestone give 
rise to low mesas or shelves in the slopes and often bear a scattered growth of 
cedars and piilons. The thickest development of the formation is 2 miles north of 
the city of Canyon, where it is 60 feet thick, while in Webster Park it is not over 10 
feet thick. 

Oarlile formation. — The Carlile formation, which consists mainly of shale, out- 
crops along the foothills of the Rocky Mountains in the anticlinal area west, south, 
and southeast of Pueblo, along the north side of the Purgatory Valley northeast of 
Alfalfa, and down the north side of the Arkansas Valley below La Junta. Small 
areas occur on divides southeast and southwest of Lamar. The formation consists 
mainly of shale of dark-gray color, averaging 200 feet thick. The middle beds are 
usually the darkest, some of them being black. At the top there is a bed of sand- 
stone varying in thickness from a few inches to 20 feet, the amount increasing to the 
west. In the same direction, also, the upper fourth of the formation becomes 
somewhat more sandy and occasional thin beds of sandstone appear. In these 
sandy beds occur numerous oval and globular concretions which often attain a 
diameter of 1 foot to 5 or 6 feet. Most of them are traversed by cracks filled with 
wine-colored calcite. The top sandstone averages 10 to 20 feet in thickness west of 
longitude 104° and attains a maximum of 30 feet at Greenwood on Hardscrabble 
Creek, and near Chandler, south of Canyon. Near La Junta it is 3 feet thick, having 
the relations shown in PI. XV, B. Usually it is soft, somewhat mixed with sandy 
shale and of yellowish color. The fossil known as Pugnellus occurs abundantly 
in the formation in the southwestern portion of the area. At the top of the Carlile 
formation in the southern and central portions of the region to which this report 
relates there is a purplish limestone 6 inches to 2 feet in thickness, in which the large 
coiled shell Prionocyclus wyomingensis is of frequent occurrence. From 50 to 75 
feet above the base of the formation in most districts, especially to the east, a thin 
limy layer containing fossils is often found. 

Timpas limestone. — The Timpas limestone is the lower member of the Niobrara 
group. Its thickness varies from 175 to 200 feet, and it consists of a basal limestone 
with overlying alternations of limestone and shale, all of light color. It is a con- 
spicuous formation in eastern Colorado, underlying all of the region east of the 
Rocky Mountains, except on the anticlines south and southeast of Pueblo and along 
the Arkansas Valley east of La Junta. In the region east of Colorado Springs it lies 
deeply buried beneath younger formations, but it appears extensively in the Arkan- 
sas Valley and in a broad belt extending across the eastern parts of Huerfano and 
Las Animas counties. A small outlier appears on the high ridge 25 miles southwest 
of Lamar, and there is continuous outcrop of the formation along the north side of 
the Arkansas Valley east of Rocky Ford. At the base of the Timpas there is a lime- 




C/5 
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I 
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UJ 
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NIOBEAEA GEOUP. 29 

stone series about 50 feet thick, which usually outcrops in a ledge or rocky slope of 
considerable prominence. (PI. XII, 5, and XV, B.) It consists of beds in layers, 
mostly 6 inches to a foot in thickness, separated by 1 to 2 inches of light-gray, cal- 
careous, limy shale. The limestone is wliite, or of a very light-gray color, becoming 
creamy white on weathering. It is compact, fine grained, and has an easy conchoidal 
fracture rudely parallel to the bedding. Owing to the latter property it usually 
weathers into flat flakes 2 or 3 inches long, differing in this respect from the Green- 
horn limestone, which cleaves into vertical flakes. The lighter color is also a dis- 
tingmshing feature. In the eastern portion of the area the rock has a more chalky 
texture. In the lower beds small nodules of a form of iron sulphide known as 
marcasite occur, which usually weather out as limonite. These are of dark-brown 
color and spherical or cylindrical in shape, usually one-fourth to three-fourths inch 
in diameter. These often accumulate in considerable number on the weathered 
surfaces. The limestone contains a characteristic fossil known as Inoceramus 
deformis, which occurs scattered at intervals through the beds. The shell is 
thick, has a roughly corrugated surface, and its larger valve has a shallow cup 
shape. Occasionally shells of a small oyster, Ostrea congesta, occur upon it, but 
these are also sometimes found separately. Much of the limestone consists of 
minute organisms known as foraminifera, which are plainly visible when thin slices, 
of the rock are examined under the microscope. Above the basal limestone are 
about 100 to 150 feet of calcareous shale of light-gray color, containing occasional 
thin beds of grayish-white limestone. Toward the top of this member there are two 
or three thicker, persistent layers of limestone, 12 to 18 inches thick, separated 
by a few feet of shales and marking the top of the formation. 

Fossils occur in the upper shales, consisting mostly of a very broad, flat Inocera- 
mus, usually covered by Ostrea congesta. In the Pueblo region the lowest stratum 
of the limestone is an impure sandy limestone 1 to 2 feet thick, of dark-gray color, 
which weathers to a yellowish-brown tint. It contains teeth of sharks and other 
fishes and numerous dark pebbles half an inch in diameter. 

Apishapa formation. — In southern Colorado the upper part of the Niobrara 
group has been separated as the Apishapa formation. It consists mainly of shale 
and calcareous shale, with a few layers of cream-colored limestones at the top. The 
thickness varies from 400 to 700 feet, but averages about 450 feet in the greater part 
of the region. Many of the shales vary in color from light gray to dark gra}^ and 
are sandy, with intercalations at intervals of dull-gray to cream-colored limy shales 
and impure limestones. The most persistent lime deposits are an alternation of 
yellow limestones and light bluish-gray limy shales JLO to 20 feet thick, marking the 
top of the formation. The lowest beds are mostly dark fissile shale about 50 feet 
thick. These are followed by about 100 feet of soft, papery shales of dark-gray color. 
The middle portion of the formation is decidedly sandy, while the upper 100 feet of 
the formation, especially in the region between Pueblo and La Junta, consists of 
dark bluish-gray fissile shale, containing two and sometimes three horizons of cream- 
colored limestone. At various horizons in the formation, especially toward the top 
and eastern part of the district, calcareous concretions occur. They are usually of 
considerable size and of lens shape. In some areas they give place to thin layers of 
concretionary limestone, which are of sufficient hardness to form ledees or low hills in 



30 ARKANSAS VALLEY IN EASTERN COLORADO. 

the smooth slopes of the adjoining beds. In the region north and east of Trinidad 
the Apishapa formation consists of about 40 feet of dark-gray to blue-gray shales 
at the base, followed by 90 feet of soft, papery shales, which grade upward through 
the blue, sandy shales into alternations of limy and sandy shales. Near the middle 
of the formation these sandy shales become coarser and flag-like, constituting about 
one-third of the formation. This member is usually somewhat bituminous. The 
upper 100 feet resembles the basal portion, but includes two and in places three 
thin layers of limestone and lens-shaped concretions of impure limestone. The 
fossil remains consist of fish scales, which are generally abundant in the shales and 
sometimes in the coarser flag-like layers. Crustacean tracks also sometimes occur. 
Fish scales from half an inch to an inch in diameter are usually abimdant. Portions 
of the Apishapa beds weather to a bright-straw color, which is a conspicuous feature 
in its outcrops. Ostrea congesta is a characteristic fossil, usually closely packed 
in masses a foot or more in diameter, and is from half an inch to an inch thick 
(PI. XIII, A). . 

Pierre shale. — The calcareous deposits of the Niobrara group are succeeded by 
a great thickness of the dark-gray Pierre shales. These underlie the deep structural 
basin extending from east of Colorado Springs south to the Arkansas Valley between 
Pueblo and Manzanola, the Florence basin, and the deep syncline in central Huerfano 
and Las Animas counties. Their thickness is over 3,000 feet in the district east of 
Colorado Springs and about Florence, but the amount diminishes to the south and 
is not more than 1,600 feet in the vicinity of Trinidad. In the vicinity of Arkansas 
River below Pueblo several distinct zones have been recognized in the formation. 
The lower beds for a thickness of 400 to 500 feet are of medium-gray color and yield 
no fossils. They contain much selenite in minute flakes. Next above is a zone of 
similar-colored shales containing less selenite and characterized by a great abundance 
of oval concretions, usually 4 to 8 inches thick and 1 to 2 feet long. These are fine 
grained, dark gray in color, and consist of carbonate of lime and carbonate of iron. 
On weathering these concretions break into small angular fragments of dark rust- 
brown color, which are often so abundant on the slopes as to give them a reddish 
color. On this account the beds have been called the "Rusty zone." Their thickness 
is about 600 feet. Beginning in the top of this zone and extending upward 100 to 
200 feet is a noticeable abundance of fossils known as Baculites compressus. Their 
form is that of a flattened cylinder, slightly tapering, and sometimes showing the 
remains of the shell. They are often a foot in length and 2 inches in diameter, but 
most of them are sraaller. This form occurs at other horizons, but is most abundant 
here. Next above the "Rusty zone" are shales of somewhat lighter color, in the 
upper portion of which occur masses of limestone, often constituting small conical 
hills, or "tepee buttes," as they have been termed (PI. XV, A). These limestone 
masses consist of coarse-textured, gray, fossiliferous rock, often rudely cylindrical 
in form and standing vertical within the shale mass. Ordinarily they are 5 to 30 
feet in diameter and of considerably greater length. As they ofi'er more resistance 
to erosion than most of the adjoining shales, the core and the fragments of rock 
derived from it often rise in conical hills 25 to 50 feet above the surrounding surface. 
Fossils occur in the limestone in considerable variety, but the most abundant 
species is a small oval bivalve known as Lucina occidentalis. The zone of the tepee 



U. S. GEOLOGICAL SURVEY 



PROFESSIONAL PAPER NO. 52 PL. XIV 




VIEW ALONG ARKANSAS RIVER WEST OF PUEBLO. BASAL TIMPAS LIMESTONE ON CARLILE SANDSTONE. 



riEERE SHALE. 



31 



buttes is apparently several hundred feet thick, but its precise stratigraphic limits 
could not be determined. In this zone there also occur smaller lens-shaped lime- 
stone, concretions, 6 to 12 inches thick and 1 to 3 feet in diameter, containing large 
numbers of beautifully preserved fossils of various kinds. In many cases the 
original shell is preserved, retaining its original pearly luster. Above the tepee 
zone the shales become darker, are less fossiliferous, and contain fewer concretions. 
The amount of selenite in small crystals increases considerably. The top of the 
formation is somewhat indefinite, the shales gradually giving place to sandy beds. 
In the region between Walsenburg and Trinidad the basal and upper zones weather 
to a yellowish-green color; the middle zone is dark gray and lead gray, occasionally 
almost black. The latter zone contains an abundance of lime and iron concretions, 
which break up readily and impart a rusty tint to the surface. 

An analysis of a typical sample of tepee rock, made by Dr. W. F. Hillebrand,'^ 
of the United States Geological Survey, is as follows: 



Analysis of limestone in tepee core. 

Silica (SiOj) 7.46 

Titanium dioxide (TiOj) 1 

Alumina (AI2O3) - J ^"''^ 

Iron sesquioxide (FejOj) .94 

Lime (CaO) 46. 98 

Magnesia (MgO) 2. 36 

Potash (K2O) , , 



Soda (NajO). 



.37 



Phosphoric oxide (P2^b) undet. 

Carbon dioxide (COj) 39. 25 

Water loss at 100° C 16 

Water loss above 100° C ...J 

Organic material J • ' ^ 



100. 00 



The limestone constituting these tepee cores bears a marine fauna. Lucina 
occidentalis is the most abundant molluscan species, forming a leading constituent 
of the rock. Inoceramus is rather common and cephalopods occur in considerable 
variety. Foraminiferal forms frequently disclose themselves under the microscope. 
The occurrence of fossil wood has also been reported from some of the cores. The 
following is a list of the molluscan species determined by T. W. Stanton, from speci- 
mens, collected by Mr. Gilbert: 



Ostrea inornata M. and H. 

Inoceramus crispii var. barabini Morton. 

Inoceramus vanuxemi M. and H. 

Inoceramus sagensis Owen. 

Lucina occidentalis var. ventricosa M. and H. 

Thetis circularis M. and H. 

Anchura (Drepanochilus) americana E. and S. 

Nautilus dekayi Morton. 

Baculites ovatus Say. 

Baculites compressus Say. 



Scaphites nodosus Owen ( ?) 

Scaphites nodosus var. quadrangularis M. and H. 

Scaphites nodosus var. brevis Meek. 

Ptychoceras crassum Whitfield. 

Heteroceras (Exiteloceras) cheyennense M. and H. (?). 

Heteroceras (Didymoceras) nebrascense. 

Heteroceras (Didymoceras) cochleatum M. and H. ( ?). 

Heteroceras sp. undet. 

Helicoceras sp. undet. 



o Gilbert, G. K., Description of Pueblo quadrangle: Geologic Atlas U. S., folio 36, U. S. Geol. Survey, 1897, p. 7. 



32 ARKANSAS YALLET IN EASTERN COLORADO. 

Fox HiUs sandstone. — The Pierre shale gives place abruptly to several hundred 
feet of sandstone which are supposed to correspond to the Fox Hills formation. 
These sandstones are most extensively exhibited in the region about Walsenburg 
and Trinidad, where they are of sufficient hardness to give rise to a prominent 
escarpment, extending from, the south side of the Huerfano Valley to the Raton 
Mesa. In this district they are known as the Trinidad formation, which here 
consists of a lower member, 85 to 90 feet thick, of thin-bedded, fine-grained,' dark- 
gray sandstone in layers 2 to 4 inches thick, with thin shale partings, and an upper 
member, 75 to 80 feet thick, of greenish-gray, heavy-bedded, massive sandstone 
which weathers to a light-gray color. This upper bed is characterized by numerous 
remains of the fossil Fucoid halymenites, which is easily recognized by the pitted 
cj'lindrical casts of the brandling stems. In the lower beds occasional poorly 
preserved baculites are found. The total thickness of the formation is about 150 
feet in the vicinity of Trinidad and about 170 feet near Walsenburg. At its top 
there are usually a few feet of brown sandstone in contact with the overlying Laramie. 
Near Trinidad the thin sandstone laj'ers of the lower member rarely exceed 3 inches 
in thickness, except near the base, where there is a prominent bed of coarser sandstone 
3 to 5 feet thick. These beds become thicker and coarser northward, and to this 
is due the expansion of the lower zone. In the district east of Colorado Springs 
there is only a small thickness of sandstone between the supposed top of the Pierre 
shale and the lowest coal beds, so that there the representative of the Fox Hills is 
but scantily developed, unless possibly there should be comprised in it some of the 
underl^nng shales ; similar conditions prevail in the eastern portion of Elbert County 
and the northern portion of Lincoln County, where the Fox Hills formation has as 
yet not been differentiated. In the Florence basin the formation consists of about 
400 feet of sandy shales, with a few limestone concretions, capped by a persistent 
bed of yellow fossiliferous sandstone 10 to 50 feet thick. 

Laramie formation. — The Laramie formation occurs in three areas in the district 
to which this report relates. One is in the wide, shallow synchne east of Colorado 
Springs; the second is in a long, deep sjoichne south and west of Trinidad and 
Walsenburg, and the third is in the deep but small syncline near Florence. The 
rocks are sandstones and shales, and among them at various horizons, especially 
in the lower beds, are extensive deposits of lignite. The sandstones are mostly 
massive, soft, and yellowish, 10 to 20 feet thick, ynih intervening bodies of shales, 
which are usually sand}' and carbonaceous. The thickness varies from 1,000 to 
2,500 feet. The Laramie rocks in the basin east of Colorado Springs have not been 
studied in detail, but in general they present the characteristics above mentioned. 
The coal is worked from lower beds at several points north, east, and southeast 
of the city. The Laramie area extends east into the northern portion of Lincoln 
County, but its limit m that direction was not accurately ascertained, owing 
mainl}^ to the cover of surficial formations. 

In the Florence district the Laramie is composed of a succession of heavy bedded 
sandstones with intercalated shales, and in the lower portions there are beds of 
workable coal. These sandstones form an escarpment surrounding the mesa 
southwest of Florence and constitute one or two small outliers, one of which is 
known as Castle Rock. In this basin there is more sandstone than shale in the 
Laramie formation. 



U. S. GEOLOGICAL SURVEY 



PROFESSIONAL PAPER NO. 52 PL. XV 




m 




A. TEPEE BUTTES IN PIERRE SHALE NORTH OF NEPESTA, COLO. 
The core of these buttes is limestone. 





B. TIMPAS LIMESTONE ON CARLILE SANDSTONE 2 MILES NORTHWEST OF LA JUNTA, COLO. 
Looking northwest. The sandstone is behind the figure. 



POST-LARAMIE FOEMATIONS. 33 

In the vicinit}' of Walsenburg the Laramie formation has a thickness of 1 ,000 feet, 
which increases to the southward, due to the thickening of the upper member and 
to diminished erosion of its upper surface, until at the State hne south of Trinidad 
the thickness is 2,500 feet. The basal beds are shales overlying the Trinidad sand- 
stone. A massive bed of sandstone a hundred feet or so from the base of the for- 
mation is persistent, and overlies an alternation of arenaceous shale, clay shale, and 
coal. Above this massive sandstone the formation is predominantly sandstone, 
but the sandstones and clay partings vary greatly in thickness. There are two 
principal groups of coal beds — one between the Trinidad sandstone and the massive 
sandstone 100 feet above, and the other above this sandstone. 

The fossil remains of the Laramie formation are limited to the characteristic 
Ostrea glabra, a unio, and a dinosaur of undetermined genus. It contains a rich 
subtropical flora, similar to the presgnt-day flora of the Gulf States, consisting of 
figs (15 species), oaks, ferns, palms, poplars, willows, and tulips. In the region 
of Golden, Colo., there are 83 species that are peculiar to the Laramie. 

CRETACEOUS (?) SYSTEM. 

Arapahoe formation. — In the Denver basin the Laramie formation is overlain 
by 600 to 800 feet of conglomerates, sandstones, and shales, which are separated by 
an unconformity and by some are believed to be of early Tertiary age. At the base 
are 50 to 200 feet of conglomerates and sandstones of increasing coarseness toward 
the mountains, while above are several hundred feet of sandy shales containing 
irregular masses of sandstones. These deposits extend far south of Denver and 
appear to be represented in the Monument Park region and east of Colorado Springs, 
but their limits and relations have not been determined. Apparently the coarser, 
lower beds increase in thickness to the south. The formation appears to be present 
in small amount in the Florence basin, where a series of conglomerates and sand- 
stones 250 to 300 feet thick is supposed to represent it. It is a prominent compo- 
nent in the Spanish Peaks basin, where it is represented by all or part of the Poison 
Canyon formation of R. C. Hills. 

Poison Canyon formation. — This formation underlies much of the high region 
rising to the Spanish Peaks between the Purgatory and Huerfano valleys. To the 
north it is separated from the underlying Laramie beds by marked unconformity, 
while in the vicinity of Spanish Peaks and southward there appears to have been 
continuous deposition between the two formations. The thickness is 2,000 feet to 
the south and 3,500 feet in the extension of the formation northwestward up the 
Huerfano Vallej". The rocks consist of coarse sandstones and conglomerates in 
beds 10 to 50 feet thick, separated by thinner masses of yellow clay. The con- 
glomerates near the middle of the formation often are not firmty cemented and 
resemble gravel beds. The overlying sandstones are light gray, weathering pink, 
while the sandstones lower in the formation are yellowish, with red blotches, but 
similarly weathering to a pink tint. No fossils have been reported, but, from the 
relations of the formation, there should be little question that it is approximately 
the same age as the Arapahoe. Some bacuhtes reported from the section of the 

4551— No. 52—06 3 



34 ARKANSAS VALLEY IK EASTERN COLORADO. 

beds in Poison Canyon doubtless were found in or were derived from the Pierre 
shales, which are overlapped by the formation in that region. 

Denver formation. — In the Denver basin the Arapahoe formation is overlain by 
several hundred feet of coarse deposits, consisting largely in the lower part of 
debris of younger eruptive rocks and in the upper part of granitic debris. It 
also includes local sheets of basalt and volcanic tuffs. Its age may be early 
Eocene. This formation is not known to extend into the Arkansas basm, but 
laSij possibty underlie a portion of the high divide near the foot of the mountains. 
Some small areas of conglomerates, sandstones, and shales overlie the supposed 
Arapahoe formation in the Florence basin, but they can not certainly be correlated 
with the Denver formation. In the higher slopes of the Spanish Peaks area, how- 
ever, there is a formation succeeding the Poison Creek beds which Mr. Hills has 
designated the Cuchara formation, and the stratigraphic succession strongly sug- 
gests that this may represent the Denver beds. 

Cuchara formation. — This formation has a thickness of about 500 feet, consist- 
ing mostly of massive, yellowish, reddish, or brownish sandstones, with 50 to 100 
feet of red, brown, and sometimes white marl, shale, and sand at the bottom. The 
sandstone is coarse and the conglomerates are often very loosely cemented, the 
pebbles largely of granite and Carboniferous debris. The formation has yielded 
no fossils, but the Denver formation has yielded 150 species of plants, only 15 of 
which are comm.on to the Laramie. 

TERTIARY SYSTEM. 

Monument Or eelc formation. — On the high divide between the Platte and Arkan- 
sas drainage basins, at the foot of the Rocky Mountains, there is an extensive 
deposit of conglomerates, sand, sandstone, gravel, and clay, known as the Monument 
Creek formation. It lies on the Laramie formation to the east and the Arapahoe 
formation to the west, and at Palmer Lake it abuts against the granite at the foot 
of the mountain. There are two members, a lower one of sands and clays and an 
upper one of conglomerate and sandstone. The latter caps numerous buttes and 
plateaus in the high region west and north of Calhan and north of Monument. 

Fossil bones of Titanotherium have been discovered by the writer'^ and Mr. C. A. 
Fisher in the upper member in the region north of Calhan and southwest of Eliza- 
beth, which indicate that this portion of the formation is of Oligocene age. The 
lower member may be Oligocene, or perhaps Wasatch or Bridger, in age. 

Nussbaum formation. — Wide areas of the High Plains adjoining the ArKansas 
Valley in eastern Colorado are mantled by loams, sands, and gravels of late Ter- 
tiary age, of which some outlying portions westward have been designated the Nuss- 
baum formation by Mr. Gilbert. These deposits consist of the /'Tertiary grit" and 
''Plains marl" of the Kansas geologists and are supposed to be of Pliocene age. 
The forraation is composed mainly of loose sand and coarse gravel, which on the 
liigher divides eastward has a thickness of more than 200 feet. Locally some por- 
tions often consist of a loose sandstone, and frequently the beds are cemented 
by carbonate of lime into a very sandy limestone ("mortar beds"), occasionally 

o Darton, N. H., Age of Monument Creek formation : Am. Jour. Sci., vol. 20, 1905, pp. 178-180. ■ 



' QUATEENARY DEPOSITS. 85 

of considerable extent. The most extensive areas cover the High Plains north 
" of Arkansas River to the east of Fountain Creek Valley, and south of the river in 
Prowers and Baca counties. Small outliers remain on many of the divides south 
of the river, west from longitude 104° to the foot of the mountains, probably indi- 
cating that originally all of the plains region was covered by the formation. In 
general the deposits have a smooth surface and slope gently to the east, but there 
is also a slope into the Arkansas Valley, especially near Boone and Fowler, where 
it approaches near to the river and ends in a prominent bluff. In Kiowa County 
two distinct terrace levels are exhibited, in the slope toward Arkansas River, with 
underlying Cretaceous beds showing in places in the intervening escarpment. 
In the high ridge extending east and north from Calhan the western margin of the 
formation presents a steep front to the west and northwest, in marked contrast 
to the gentle easterly slopes. The eastern limits of the formation north of Arkan- 
sas River are usually indefinite, owing to wash of the deposits down the general 
slope. South of Lamar the formation caps an elevated smooth-topped ridge and 
is terminated to the north by an abrupt slope, especially at the head of Clay Creek. 
To the east it descends rapidly and crosses Two Butte and adjoining creeks. 

QUATERNARY SYSTEM. 

Alluvium. — The largest areas of alluvium in this district are along Arkansas 
River below Pueblo. The width of the bottom lands which they constitute varies 
from three-fourths of a mile to a mile, and the thickness of the deposit is 50 to 60 
feet in the central portion of the valley. The materials are mostly fine sands and 
loams laid down by the river at various stage's ; in times of flood more or less new 
material is deposited, especially on the lower flats. Above Pueblo, where the river 
flows in a narrower valley, the alluvial flats are narrower. 

There are alluvial bottom lands along Fountain Creek and nearly all of the 
larger branches of the Arkansas, the only exceptions being in some of the narrower 
portions of the canyons in the southwestern part of the area. Higher terrace 
levels appear in places, capped by sand and gravel, products of an earlier period 
of Quaternary deposition. 

Dune sands. — Sands which have been heaped up by the wind occur extensively 
along the south side of Arkansas River from Las Animas eastward, often in a belt 
a mile wide. Dunes of considerable prominence are found south of Lamar and 
Granada. Portions of the Nussbaum formation give rise to sand dunes, notably 
in the region north of Nepesta and in wide areas in Kiowa, Cheyenne, and Lincoln 
counties. Between Rush Creek and Big Sandy nearly all of the land is capped 
by sand dunes derived from the Nussbaum formation. 

IGNEOUS ROCKS. 

In the Rocky Mountain Range adjoining the Arkansas Valley are extensive 
bodies of igneous rocks, mostly of Tertiary age. Those in the vicinity of Pikes 
Peak and Cripple Creek have been described by Doctor Cross" and others. The 
extensive series of dikes in the Spanish Peaks and adjacent slopes have been 

a Cross, Whitman, Description of Pikes Peak quadrangle: Geologic Atlas U. S., folio 7, U. S., Geol. Survey, 1894. 



36 ARKANSAS VALLEY IN EASTERN COLORADO. 

described by Mr. R. C. Hills'* and the reader is referred to these publications for 
details. The distribution of the rocks is shown in PI. VI. 

The Mesa de Maya and the Raton Mesa consist of remnants of extensive 
outflows of basalt of late Tertiary or Quaternary age, and in their vicinity are a 
number of similar smaller outliers of the same material, as shown in PI. II. On 
the south side of the Mesa de Maya the basalt is seen to overlie an outlier of later 
Tertiary gravels, which indicates that the age is post-Pliocene. 

In the Two Butte uplift igneous rocks appear, as described by Mr. G. K. 
Gilbert,^ in a laccolithic mass and in numerous dikes. 

MANITOU EMBAYMENT. 

West of Colorado Springs there is a westward deflection in the Front Range 
of the Rocky Mountains, in which lies a thick development of the Paleozoic rocks. 
The recess is about 4 miles deep and is due to a westward trend of the granite 
on the north side and a profound fault on the southwest side, forming a reentrant 
angle of which the apex is at Manitou. In PI. XVI the principal geologic rela- 
tions are shown, and they are especially brought out by the central cross section 
on that plate. To the north and south the "Red Beds" usually lie against the 
granite at the surface, but in the embayment the older limestones and sandstones 
appear at the surface. It is probable that east of the mountain front these rocks 
extend far to the north and south, but on either side of the embayment they have 
been eroded from the granite slopes and overlapped by younger sediments. The 
embayment probably was a valley at the time of this erosion epoch, and the sedi- 
ments contained in its deeper portion were not removed. Its southwestern margin 
has been cut off by the great fault, which uplifted the strata so high that they 
were long ago removed by erosion. 

The embayment continues far to the northwest from Manitou, but the strata 
which it formerly contained are removed for the first few miles. A small area 
of "Red Beds" and underlying limestones remains in this area in Manitou Park, 
on Trout Creek, as shown on the geologic map (PL VI). From the vicinity of 
Manitou northward to beyond Glen Eyrie Creek the basal strata are sand- 
stones and limestones of Cambrian and Ordovician age, and these appear again 
in a small area west of Monument Park. Most of their features were described 
by F. V. Hayden and Dr. A. C. Peale,<= and by Prof. W. O. Crosby,*^ in a detailed 
account of the Archean-Cambrian contact near Manitou. 

The basal bed is a sandstone averaging about 50 feet thick, usually light 
colored and moderately fine grained in its lower beds, and red or pink with greenish 
layers in its upper ones. It contains Cambrian fossils (determined by Mr. Walcott 
as Oholus (Linguella) similis), and more or less glauconite. The sandstone lies on 
the granite along a remarkably smooth plain, which shows occasional local erosion 
irregularities, and the contact is sometimes faulted or flexed. Many details of 
these contact phenomena are described in the paper by Professor Crosby, just 

Jr 

1 Hills, R. C, Description of Spanish Peaks, Walsenburg, and Elmoro quadrangles: Geologic Atlas U. S., folios 71, 68, and 58. 
b Gilbert, G. K., Laccoliths in southeastern Cokorado: Jour. Geol., vol. 4, 1S96, pp. 816-825. _ 
c U. S. Geol. and Geog. Surv. Terr., Seventh Ann. Rept., 1874, pp. 193-273. 
d Bull. Geol. Soc. America, vol. 10, 1899, pp. 14-164, pl.s. 14-18. 



U. S. GEOLOGICAL SURVEY 



PROFESSIONAL PAPER NO. 62 PL. XVI 



EXPLANATION 



Laramie and 
overlying beds 



Pierre and 
Fox Hills ? 



Niobrara 



Benton 



"Dakota^' 



Morrison 



Chugvrater 



Fountain 



Millsap 



Manito-u 



/Vr/>^ 



Granite 



Faults 



C . Cheyenne Mln . 

G. Glen Eyrie 

B. Blodgett PecOc 




** miles 



Base o^sect/ons I's 3000 feeL above sea level 
MAP AND CROSS SECTIONS SHOWING GEOLOGIC RELATIONS IN THE MANITOU EM BAY WENT AN D TO NORTH AND SOUTH. 



MANITOU EMBAYMENT. 37 

referred to. Fine exposures may be seen on both sides of Fountain Creek; which 
the formation crosses 1 ^ miles above Manitou, in WiUiams Canyon, and at Glen 
Eyrie. The formation dips gently to the southwest and extends for some distance 
west up the divides between the valleys above mentioned. It ends abruptly at a 
point a mile north of Glen Eyrie, where it is overlapped by Fountain " Red Beds," 
but reappears for a short distance in a local embayment a mile farther north, and 
Mr. W. T. Lee reports it on Deadman Creek southwest of Monument station. 

Overlying the Cambrian sandstone are several hundred feet of limestones, 
of which the lower portion is Manitou, containing Ordovician fossils, while the 
upper members, according to Professor Grabau, ® contain Mississippian fossils. 
This limestone caps the sloping ridges west and south of Manitou and appears 
extensively in the intervening canyons, especially in Williams Canyon. Its outcrop, 
together with that of the underlying sandstone, is terminated by overlap of the 
Fountain formation, a mile north of Glen Eyrie, and reappears in the small embay- 
ment west of Monument Park. In this outlier there are exposed, lying on the 
granite, 30 feet of dark-gray, coarse sandstones, thin bedded and glauconitic at 
the top, overlain by 20 feet of bright-red, sandy limestone with Cambrian fossils, 
and by 50 feet of massive, pure, fine-grained, light-gray limestone. On this lime- 
stone, which apparently is Manitou, lies an impure limestone varying from gray 
to buff in color, with a heavy breccia at its base, the latter probably marking an 
unconformity. The limestones are cut off by a fault, bringing down the Morrison 
and overlying ''Dakota," but a short distance to the north and south the Fountain 
" Red Beds " are exposed lying directly on the granite. 

The Fountain formation occupies a wide area in the Manitou embayment, 
from Glen Eyrie southward. On the west side of the area the dips are low, but 
to the east they become nearly vertical, a feature exhibited in the ledges at and 
near the Gateway to the Garden of the Gods, as shown in PI. IX, A. The rocks 
consist of coarse sandstones, in part conglomeratic and mostly of red color, although 
some portions are mottled with gray. The thickness is 1,000 feet or more. From 
Manitou to Glen Eyrie the formation lies unconformably on the Millsap limestone, 
but no marked divergence of dip or erosion features was observed. To the south 
the formation is cut off by a gr'feat fault, which brings it in contact with the granite. 
The outcrop of the formation extends northward from Glen Eyrie, where, as above 
stated, the red grits directly overlap the granite. In places in their northward 
extension they are cut off by faults and extensively overlapped by Tertiary forma- 
tions. At the top of the formation there is the well-marked Lyons sandstone, 
which gives rise to the prominent white ridge a few rods east of the Gateway to 
the Garden of the Gods. This formation is overlain by the upper "Red Beds," 
which I have designated the Chugwater formation. The latter consists mainly 
of soft red shales with layers of limestone in its lower portion, with a thick bed 
of gypsum at the top. This gypsum bed is 30 feet thick at the Gateway to the 
Garden of the Gods, and for some distance north. Owing to talus, faults, and 
overlaps of younger formations the Chugwater formation is not exposed in the 
region between West Monument Creek and Perry Park, and southeast of Manitou 
it is cut off by the great fault. 

a Girty, G. H. Carboniferous formations and faunas of Colorado: Prof. Paper V. S. Geol. Survey No. 16, 1903, p.l68. 



38 ARKANSAS VALLEY IN EASTERN COLORADO. 

The formations overlying the Chugwater formation in the Manitou embay- 
ment are the usual succession of Morrison, "Dakota," Benton, Niobrara, and 
Pierue, all of which, except the latter, are cut off by the great fault southwest of 
Colorado Springs. There is also a local interruption in the succession a short 
distance northwest of Colorado City, owing apparently to a short fault cutting off 
the "Dakota" and adjoining beds. The Morrison formation west of Colorado 
Springs exhibits its usual characteristics. Light-colored massive shales predomi- 
nate, but some fine-grained sandstones and several thin limestone layers are 
included. Portions of the shale are of grayish-green and maroon tints. The 
formation lies directly on the 30-foot bed of gypsum at the top of the Chugwater 
formation. The overlying "Dakota" sandstone varies from 125 to 200 feet in 
greater part, and is in two massive beds, with shales between. As above stated, 
the sandstone disappears for a short distance northwest of Colorado City, prob- 
ably owing to a local fault. The Graneros shale is 240 feet thick. The Green- 
horn limestone is well defined and 75 feet thick, consisting of thin beds of lime- 
stone with dark shale alternations and containing large numbers of Inoceramus 
labiatus. The Carlile formation, about 250 feet thick, is terminated by the usual 
bed of sandstone, which is overlain directly by the Timpas limestone. This sand- 
stone and limestone form a prominent hogback extending from north of Glen Eyrie 
to Bear Creek Canyon, beyond which the Timpas limestone continues nearly to 
Cheyenne Creek, where it is finally cut off by the great fault. 

In the region west of Monument Park the Morrison, "Dakota," Benton, and 
Niobrara beds appear at intervals, but they are mostly obscured by talus and 
overlaps. A small exposure of the Timpas limestone appears southwest of Monu- 
ment station, as shown in PI. XVI. It dips steeply to the east and appears to 
be overlapped by Tertiary formations. 

CANYON EMBAYMENT. 

General structure. — In the region west of Pueblo there is a deep westward 
deflection or reentrant in the Rocky Mountain Front Range, in which the sedimen- 
tary strata extend to a short distance west of the city of Canyon. The granite 
Front Range, which is so prominent west of Colorado Springs, exhibits an anticlinal 
structure to the south, and the granite in this anticline pitches beneath the sedi- 
mentary strata northeast of Canyon. The sedimentary strata in the syncline on 
its west side extend northward through Garden Park to the north line of Fremont 
County, beyond which the granite rises. The prolongation of the anticline, greatly 
reduced in height, is traceable southward to Huerfano Canyon, crossing Arkansas 
River 6 miles northwest of Pueblo. The syncline deepens to the south, and in the 
region southwest of Florence holds a deep basin of Laramie coal measures. Near 
the south line of Fremont County its western side is faulted so that the Laramie 
sandstones are in contact with the granite. The west and south sides of the Canyon 
embayment consist of the Wet Mountain Range, an anticlinal ridge of granite 
which extends southeastward and finally pitches down near Huerfano River. 

In the Canyon embayment are found formations from Cambrian to latest 
Cretaceous or early Tertiary, presenting considerable complexity in overlap and 



U. S. GEOLOGICAL SURVEY 



PROFESSIONAL PAPER NO. 52 PL. XVIt 




A. VERTICAL "RED BEDS" NEAR COLORADO CITY, COLO. 
Garden of the Gods to the left; ridge of Niobrara limestone to right. Photograph by I. C. Russell. 




B. MORRISON FORMATION ON GRANITES WEST OF GRAPE CREEK, 4 MILES SOUTHWEST OF CANYON, COLO. 

Looking north-northeast. The pron-.iref.t ledge cf sandstone is "Dakot-," 



GARDEN PARK AREA. 39 

structural relations. The principal features are shown in PI. XVIII. The rela- 
tions shown north of latitude 38° 30' are compiled from the Pikes Peak folio by- 
Whitman Cross. The dominant structural features have already been alluded to. 

Garden Park area. — Oil Creek Valley lies in a syncline pitching southward and 
exhibiting formations of Ordovician, Carboniferous, and Cretaceous ages. On the 
west side of the creek, north of Garden Park, is an extensive area of Ordovician 
limestones and sandstones. At the base is Manitou limestone with a basal cherty 
and quartzitic portion of Cambrian age lying on the granite and gneiss. Next 
follows the Harding sandstone, surmounted by long slopes of Fremont limestone. 
So far as observed, this sequence is general for an extensive area about Garden Park. 
In portions of the area faults cut out some, or all, of the beds. On the granite 
slopes east of the creek numerous small outliers occur. The Manitou limestone is 
100 feet thick and consists of fine-grained, pink or reddish dolomite with Ordovi- 
cian fossils. Cherty limestone at the base yields fragments of the trilobite P^cAo- 
varia. The Harding limestone consists of fine- ' and even-grained saccharoidal , 
sandstone in alternating beds of light-gray or pinkish and variegated colors, with a 
few bands of dark-red or purplish sandy shale. The maximum thickness is about 
100 feet. The lower part is sometimes calcareous and locally develops into a thin, 
fine-grained dolomite. It is succeeded with apparent conformity by the Fremont 
limestone, which is a bluish-gray or pinkish dolomite of uneven grain, sometimes 
sandy, weathering to very rough surfaces. Its thickness is about 100 feet, and it is 
especially characterized by the occurrence of chain coral (Haly sites catenulatus) , 
which often occurs in masses 2 feet in diameter. It also contains other fossils of 
later Trenton age. 

The Fremont limestone gives rise to long sloping plateaus on the west side of 
Oil Creek north of Garden Park. At the north end of the park the Fremont 
limestone is overlain by Millsap limestone in a narrow outcrop about 1\ miles long. 
Thirty feet of the formation are exposed consisting of thinly bedded, variegated, 
dolomitic limestone, with a few thin sandstone layers. Chert nodules in the upper 
limestone layers carry casts of characteristic Mississippian fossils. 

The greater part of Garden Park is underlain by the Fountain formation, which 
reaches a thickness of about 1,000 feet. It lies on the Millsap limestone above 
mentioned, but overlaps onto the Fremont limestone, presenting unconformable 
contacts in both cases; for part of its course it is cut off by extensive faults, as 
shown in PI. XVIII. The Fountain beds consist of red sandstone, grits, and con- 
glomerates, heavily bedded and with much feldspathic material derived from the 
adjacent granite. The conglomerate layers contain many pebbles of hard, pre- 
Cambrian quartzites and of limestones, quartz, and cherts. 

The Morrison formation appears extensively along the south and west sides of 
Garden Park, where the thickness is about 350 feet. It is separated from the Foun- 
tain formation by unconformity, but does not present divergence of dip or evidence 
of deep channeling. The materials are mainly greenish, pink, or gray shales and 
marls. Sandstone occurs at the base and also at numerous horizons in the upper 
part of the section, but the beds vary in thickness and extent. In the sandstone 
deposits about 100 feet from the top of the series, at the locality shown in PI. X, B, 
large numbers of saurian remains have been obtained. Fresh-water shells also occur. 



40 ARKANSAS VALLEY IN EASTERN COLORADO. 

Gypsum is locally developed, and a thin v limestone occurs in the lower portion of 
the formation. 

The Morrison formation is succeeded in regular order by "Dakota" sandstone, 
which caps high ridges south and west of the park, presenting its usual charac- 
teristics and having a thickness of about 300 feet. Southeast of Garden Park lie 
Sixmile, Eightmile, and Cemetery parks, valleys which mark the eastward and 
northeastward extension of the Fountain " Red Beds" across the north end of the 
Front Range anticline. On the north side of these parks are slopes of Ordovician 
limestones and sandstones, comprising Manitou and Harding, with Fremont as far 
east as Eightmile Creek, northeast of which the Fountain formation lies directly on 
the Harding sandstone. Outliers of Manitou limestone occur at intervals high on 
the granite slopes north. South of the three park§ there is a continuation of the 
"Dakota" hogback, with Morrison formation in its northern and northwestern 
slopes. On Eightmile Creek the Fountain and associated formations are traversed 
by a prominent fault which brings up the granite in two prominent knobs on either 
side of the creek. On Wilson Creek, 8 miles northwest of Garden Park, some small 
outliers of Morrison formation lie directly on the granite and gneiss and in part are 
overlapped by small areas ol "Dakota" sandstone. Two similar areas of these two 
formations occur still farther northwest on the small branch of High Creek. Three 
miles southwest of Garden Park is Shaws Park, underlain by a zone of Fountain 
"Red Beds" outcrops which extend southward to Arkansas River west of Canyon. 
On the west side of this zone the Ordovician limestones and sandstones extend far up 
the mountain slopes, while on the east side is a hogback of Dakota sandstone with 
Morrison formation in its western slope. At the north end of Shaws Park there is a 
prominent fault, which crosses Wilson Creek nearly at right angles and brings forma- 
tions from Ordovician to Cretaceous into contact with the pre-Cambrian rocks, as 
shown in PI. XVIII. 

West of Canyon. — In the mountain slopes and hogback west of Canyon there is 
presented the southward extension of the formations of the Garden Park area. The 
formations all dip steeply to the eastward and there are numerous exposures of all the 
beds. The high mountain range west, consisting of granite and gneiss, is traversed 
by Arkansas River in a deep canyon known as the Royal Gorge. On the lower 
eastern slopes of this ridge the Ordovician rocks are extensively exhibited. The 
valley of Sand Creek is in the Fountain "Red Beds." The main hogback west of 
Canyon consists of "Dakota" sandstone, with Morrison formation on its west side 
and Benton shales on its east slope. There is also a subordinate hogback of small, 
sharp ridges due to the Timpas limestone of the Niobrara formation. To the east 
there is a broad, deep basin containing Laramie coal measures. 

The principal features of distribution of the formations are shown in the middle 
portion of Pl.XVIII. On the mountain road 4-^ miles northwest of Canyon the Man- 
itou limestone lies directly on the granite. It is 10 feet thick and contains bands 
of chert. Next above is characteristic Harding sandstone, pink and buff, except 
at the top, where there is a characteristic succession of reddish shales. The Fre- 
mont limestone appears with its usual characteristics, and apparently also the 
Millsap limestone, although no Carboniferous fossils were observed at this place. 
The upper portion of the limestone presents a very irregular contact with congloni- 



U. S. GEOLOGICAL SURVEY 



PROFESSIONAL PAPER NO. 52 PL. XVIIl 




mm Millsap 
jg^i^^j^^ Ordovician 



\-:<r/-7A Granite 
l»^'-.^r->.^,'-r1 Igneous 
^3 Faults 

SCALE 



^ 1 , I - I I all! 

-\ Base of sections is 3000 feet /--'•.'/"' vv-'/^'-^-^v 
^ above sea leveL^-r^'Ti T'/^i"^riAr,V''v<?'0' v'* ' 

'"-' ' ■■'-'• ' til -.-A/' I ' -' ^ ^ y^'' — ' ' i\"> \ /_ ,__ 



MAP AND CROSS SECTIONS OF "DAKOTA" AND ASSOCIATED FORMATIONS IN THE CANYON EMBAYMENT, 

COLORADO. 



ORDOVICIAN WEST OF CANYON. 41 

erate beds at the base of the Fountain formation. A typical exposure of this feature 
is shown in PL XX. The conglomerate is about 80 feet thick and is succeeded by 
about 1,000 feet of red sandstones and grits extending to the base of the "Dakota" 
hogback. In the vicinity of Harding's quarry, 2 miles northwest of Canyon, the Man- 
itou limestone is seen to have disappeared and it is not found again in the extension 
of the beds southward. The following detailed section in this vicinity was inade 
by Mr. C. D. Walcott:" 

Geologic section of Fremont limestone and Harding sandstone near Harding's quarry, northwest of Canyon, Colo. 

Fremont limestone: Feet. 

Compact, hard, ligbt-gray limestone, breaking into angular fragments, but with a band of purple 

and gray calcareo-arenaceous shale at the base, containing a large Trenton fauna 45 

Dark, reddish-brown sandstone 10 

Hard, compact, light-colored limestone with fossils 45 

Gray, siliceous, magnesian limestone, somewhat ferruginous in lower portion; weathers locally to 

reddish friable rock, except that near base limestone weathers into rough irregular cliffs with 

many caverns and holes; corals and other fossils 170 

Red and purple fine-grained, argillaceous, arenaceous shale; fish-plate fragments 2-4 

Harding sandstone: 

Coarse purplish sandstone in several layers with gray layers above 11 

Gray and buff sandstone. 7 

Fine-grained, argillaceous, arenaceous shale 3 

Massive gray and reddish sandstone with thin irregular beds of reddish-brown, sandy shale in lower 

portion ; numerous fish remains 20 

Reddish-brown, sandy shales, partly calcareous in some layers; fish plates and other fossils 

abundant 7 

Compact, thinly bedded, reddish and gray sandstone passing into a gray and more massively 

bedded, somewhat friable sandstone that changes at 25 feet up into a purplish-tinted, somewhat 

coarse, friable sandstone ; dip 40° 33 

Coarse, light-gray sandstone 5 

Granite. 

Overlying the Fremont limestone are 15 to 30 feet of impure variegated banded 
limestones, with interbedded sandstones and argillaceous beds containing Mississip- 
pian fossils. The unconformity between the two limestones representing Silurian 
and Devonian time is not marked by discordance of dip nor by any noticeable erosion 
features. On the north side of Arkansas River, at the mouth of the Royal Gorge, the 
Ordovician beds are well exposed, lying on granite and gneiss and dipping steeply 
eastward. There is a basal conglomerate merging upward into hard gray to pink 
sandstones, in part coarse grained, 100 feet or more in thickness. These are suc- 
"ceeded by 80 feet of reddish-brown shales and thinly bedded sandstones, 70 feet of 
gray to pink sandstones (mostly soft and massive) , 8 feet of red shales, 30 feet of gray 
to pink sandstones (mostly massive) , followed by a talus-covered interval of about 
100 feet, east of which appear ledges of Fremont limestone merging upward into a 
few feet of gray sandstone. The latter is overlain by the basal conglomerate of the 
Fountain formation. On the opposite side of Arkansas River the Harding sandstone 
is about 200 feet thick and is overlain by about 100 feet of limestones, in part sandy, 
capped by a 20-foot bed of light-gray sandstone. On the irregular upper surface of 
the latter lie coarse conglomerates at the base of the Fountain formation. Both the 

o Wa'.cott, C. X>., Discovery of a vertebrate fauna in Ordovician strata: Bull. Geol. See. America, vol. 3, 1892, pp. 155-157. 



42 ARKANSAS VALLEY IN EASTERN COLORADO. 

Harding sandstone and the Fremont limestone end a short distance to the south on 
Grape Creek, the sandstone terminating at a point about three-fourths of a mile 
south of Arkansas River. The Fountain formation also thins rapidly, and at a point 
a mile south of the river is only about 250 feet thick, including a basal red conglom- 
erate. In this vicinity the unconformity at the base of the Morrison is very marked, 
there being much deep channeling in the "Red Beds" surface. 

On the east side of Grape Creek, just above its mouth, there are nearly continu- 
ous exposures from the granite to the "Dakota" sandstone. At the base are about 
150 feet of massive gray sandstones, pinkish in their upper portion. These are suc- 
ceeded by about 50 feet of soft gray sandstone, with some limestone layers, 50 feet of 
limestone (Fremont), 10 feet of red sand and sandstone, about 900 feet of Fountain 
beds (with conglomerate and arkose at the base), and the massive pinkish-gray sand- 
stone 30 feet thick at the top. The latter is a noticeable feature west and northwest 
of Canyon. In a small canyon cut through the hogback ridge 1^ miles south of the 
mouth of Grape Creek there are extensive exposures. On the west there is, first, the 
granite, overlain directly by red and gray conglomerates and grits of the Fountain 
formation, here not over 30 feet thick; then follow Morrison shales about 300 feet in 
thickness, presenting the usual characteristics. The " Dakota" sandstone presents the 
features shown in PL X, A. It has a lower member, 90 feet thick, of massive bufp 
sandstone; a middle member, 100 feet thick, of dark-gray shales'^ with buff sand- 
stone partings, and an upper member, 100 feet thick, of massive buff sandstone 
which rises to the crest of the hogback ridge. The upper portion of this member 
grades into the Graneros shales through about 15 feet of beds of passage. The 
Graneros formation is 250 feet thick and is succeeded by 50 feet of typical Greenhorn 
limestone in thin layers with shale partings. Large numbers of Inoceramus labiatus 
occur in the upper portion of the limestone. 

The Carlile formation consists of 200 feet of dark shale, with 2 J feet of sandy 
limestone with oysters at the top. The basal portion of the Timpas limestone is in 
massive beds 30 feet or more thick, followed by 600 feet of Timpas and Apishapa 
beds. Much shale occurs in the lower and middle portion of the latter, and the usual 
bright-yellow weathered beds at its top. 

The "Dakota" hogback extends southwestward to the granite slopes at the foot 
of the Wet Mountain Range, where all of the strata from the Morrison to the basal 
Pierre are cut off by the east-west fault, as shown in PL XVIII. Along the main road 
from Canyon to Webster Park, on the hillside above the last big bend in Grape Creek, 
there is a well-faarked fault cutting off the "Dakota" sandstone on the west and 
bringing it into contact with two small masses of limestone, apparently Fremont, 
underlain by sandstone, probably Harding, which lies directly on the granite to the 
west. A short distance south of where the road crosses this fault the "Dakota" 
sandstone is seen to be underlain by the Morrison formation, which lies directly on 
granite, showing a definite overlap. This relation is repeated on the west side of 
Grape Creek, as shown in PL XVII, B. In both of these contacts the dips are very 
low, and faulting is out of the question. 

Four miles due south of Canyon the Pierre shale appears to extend directly to 
the granite, from which it is apparently separated by the extension of the fault which 

a In the summer of 1905 Mr. Stanton discovered Comanche fossils in these shales. 



U. S. GEOLOGICAL SURVEY 



PROFESSIONAL PAPER NO. 52 PL. XIX 




^- ^V/ii^ 




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A. SHALE MEMBER LYING BETWEEN TOP OF HARDING 
SANDSTONE AND BASE OF FREMONT LIMESTONE ON 
MOUNTAIN SLOPE NORTHWEST OF CANYON, COLO. 

Photograph by C, D. Walcott. 




HARDING SANDSTONE ON GNEISS AND SCHISTS U MILES NORTHWEST OF CANYON, COLO, 
ng north from below spring west of Harding's quarry. The man's feet are on the contact. Photograph by C. D. Walcott. 



U. S. GEOLOGICAL SURVC^ 












PROFESSIONAL PAPER NO 


52 


PL. XX 




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CONGLOMERATE AT BASE OF "RED BEDS" LYING U NCO N FORM ABLY ON MILLSAP LIMESTONE, 4 MILES 

NORTH-NORTHWEST OF CANYON, COLO. 



Looking northeast. 



RELATIOTSrS SOUTH OF CANYON. 43 

cuts off the "Dakota" sandstone and overlying formations along the foot of the 
mountains westward. The fault appears to die out at the point where the main 
mountain slope turns abruptly to the south. In this vicinity the "Dakota" sand- 
stone and overlying formations reappear at first in a steep-dipping monocline with 
Laramie sandstones less than a mile distant from the granite. At one point 2 miles 
northwest of Chandler the "Dakota" sandstone lies directly on the granite and is 
overlain by 400 feet of Benton shales, including the Greenhorn limestone and 25 
feet of sandstone at the top of the Carlile formation, on which lies the Timpas lime- 
stone. West of Chandler a syncline and anticline develop, the latter marked by a 
prominent ridge, which is due to the top sandstone of the Carlile and the overlying 
Timpas limestone. These flexures extend nearly to Oak Creek, where they die out. 
Near the foot of the mountain slope, 2 miles southwest of Chandler, the "Dakota" 
sandstone is underlain by 300 feet of Morrison shale, under which for a short distance 
the Harding sandstone and the Fremont limestone appear. The following section 
was measured by Mr. C. E. Siebenthal, in beds dipping 80°: 

Geologic section 2 miles southwest of Chandler, Colo. 

Feet. 

Morrison shale 300 

Massive white hmestone 40 

Massive, red, dolomitic limestone 40 

Red shale and brown sandstone, with fish scales 25 

Hard and soft sandstones, interbedded 30 

Granite. 

A short distance south of this locality a fault develops which cuts off the Morri- 
son, "Dakota," Benton, Niobrara, and Pierre beds in succession and immediately 
south of Oak Creek brings the Laramie beds into contact with the granite. This 
relation continues to the southern margin of Fremont County, or to a mile south of 
Neulan Creek. At the southern margin of PI. XVIII, which is about a mile south of 
the southern margin of Fremont County, the Pierre shale and granite are in contact 
along this fault line. 

EAST SIDE OF GREENHORN MOUNTAIN. 

Greenhorn Mountain is a southern extension of the Wet Mountain Range, 
and it terminates southward in a south-pitching anticline, in the same manner as 
the eastern Front Range does northeast of Canyon. Along its east side, from Hard- 
scrabble Creek to its southern termination at Huerfano River, a considerable variety 
of overlap relations are presented. The principal features are shown in PL XXII 
(constructed largely from the Walsenburg and Pueblo folios). The lowest beds 
exhibited appear only in small outliers west of Beulah, where a white sandstone 
about 30 feet thick is found, supposed to represent the Harding limestone, lying upon 
gneiss and overlain by limestone supposed to represent the Millsap. Of the lime- 
stones 175 feet are exhibited, consisting of gray and purple rocks with some shale, 
especially in the lower part. The limestone is classified as Millsap by the occurrence of 
Sfirifer rockymontana, which appears in the middle of the series, but it is possible that 
the lower beds are Ordovician. The Fotmtain formation appears extensively along 
the valleys of North and South creeks, at the head of Red Creek, and to a limited 



44 ARKANSAS VALLEY IN EASTERN COLORADO. 

extent on Hardscrabble Creek. The rocks consist chiefly of brownish-red sandstones, 
mostly of coarse texture and containing a considerable proportion of feldspar grains. 
The upper beds include red and chocolate-brown shale, and at the base there is much 
coarse conglomerate containing pebbles and bowlders of granite and gneiss. Near 
Beulah the strata dip eastward at angles of 10° to 20°; the outcrop has a breadth of 
about 1^ miles, and the thickness of the formation is about 2,000 feet. Four miles 
south of Beulah the Fountain formation is cut off by a fault. On the head of Red 
Creek the thickness is much less, and north of Hardscrabble Creek it is in places 
not over 20 feet thick and is occasionally overlapped by the Morrison formation. 

At the south end of the Greenhorn Mountain Range, under the Morrison forma- 
tion, there appear about 200 feet of red sandstones, which have been termed the 
Badito formation by R. C. Hills, who states that it apparently corresponds to part of 
the Fountain formation. The lower half of the formation consists of very coarse 
brownish-red conglomerate, and the upper part is a brick-red sandstone, generally 
massive, but in part thin bedded. The Morrison formation appears at intervals along 
the east side of the Greenhorn Mountain Range, usually lying on the Fountain forma- 
tion but overlapping the granite on Muddy Creek and near the south end of the moun- 
tain. At St. Charles Canyon it is in contact with the granite, apparently because of 
a fault. The rocks are chiefly massive clays of light color, with thin beds of limestone, 
sandstone, and gypsum. The lower beds are mostly white and the upper ones choco- 
late-brown and maroon. On the slopes of Hogback Mountain the formation consists 
chiefly of red shale with a few layers of hard red sandstone, in all about 70 feet thick. 
Near the southern end of Greenhorn Mountain the Morrison formation is 270 feet 
thick and dips steeply down the mountain slope. The lower beds consist of about 60 
feet of soft white sandstone having a conglomerate layer at the base. "This is fol- 
lowed by hard shaly beds of pinkish and greenish tints, which break into fragments 
with conchoidal fracture. The upper portion consists of variegated shales and clays 
alternating with bands of hard, fine-grained limestone, often containing vermilion- 
colored cherts. One band of conglomerates a few feet thick contains green pebbles. 
At one point the basal sandstone overlaps the Badito formation and rests on the 
gneiss at an angle of 15°."" 

The " Dakota " sandstone extends along the foothills from Adobe Creek to the 
end of the mountain /just north of Huerfano River, except for a short distance near 
Muddy Creek, where it is dropped by a fault. To the south it lies directly upon 
the granite, but at St. Charles Canyon and northward it is underlain by older 
sedimentary rocks, and this also is the case at the south end of Greenhorn Mountain. 
On the headwaters of Muddy Creek the formation spreads out extensively in a 
shallow basin, as shown in PI. XXII, where it appears lying directly on the granite. 
The outcrop is also of wide extent on St. Charles River and northward to Red Creek. 
In Barton Park the formation occupies a shallow syncline which crosses Hard- 
scrabble Creek near the junction of North and South forks. Just east of this place 
the anticline east of the syncline pitches down and at Greenwood the "Dakota" 
sandstone gives rise to a prominent anticlinal ridge. The formation presents its 
usual features of a light-colored, massive sandstone partly coarse grained, espe- 
cially in the lower beds, where there is more or less conglomerate ; the color is mostly 

a Hills, R. C, Description of the AValsenburg quadrangle: Geologic Atlas U. S., folio 68, U. S. Geological Survey, 
1900, p. 1. 



U. S. GEOLOGICAL SURVEY 



PROFESSIONAL PAPER NO. 52 PL. XXI 




A. TWO BUTTE, IN SOUTHWEST PROWERS COUNTY, COLO. 
Exeter sandstone at top of "Red Beds'' uplifted by igneous intrusion. 




B. WATER HOLE IN "DAKOTA" SANDSTONE NEAR THATCHER, COLO. 



CAMBRIAN CONDITIONS. 45 

pale buff. Considerable shale is included at some localities, especially in the middle 
of the formation. The thickness varies. In the vicinity of Beulah Mx. Gilbert 
reports 650 feet, consisting almost entirely of sandstone. Farther north and south 
the thickness averages about 300 feet. Along the southern slopes of Greenhorn 
Mountain there is included in the lower half of the formation a persistent bed of 
gray shale 8 to 10 feet thick. The upper sandstones, aggregating 100 to 150 feet 
in thickness, are light gray when unweathered, of fine grain, close texture, and 
regular bedding. "The lower two-thirds of the formation consists, as a rule, of 
yellowish-gray sandstone of a coarse, porous texture, and some of the layers are 
really fine conglomerate. Cross-bedding is rather common." " 

The Graneros and Carlile formations, with the intervening Greenhorn lime- 
stone, extend all along the east side of the range and present no special features of 
stratigraph}^ or overlap. They are traversed by numerous faults, especially in the 
area between Greenhorn and Rush creeks, as shown in PI. XXII. _ 

GEOLOGIC HISTORY. 

The Great Plains region is underlain by sedimentary rocks affording a record 
of physical geography from Cambrian time to the present, but owing to the lack of 
knowledge of the relations of some of the deeply buried rocks and to our imperfect 
interpretation of many features of different geologic epochs, only an outline of the 
general sequence of events can be given. One significant feature is that some of 
the conditions were widespread, for there is remarkable uniformity in the resulting 
products. There were undoubtedly many marine submergences and several periods 
of emergence in which the surface was sculptured by running waters, especially in 
the later epochs. 

Cambrian. — During early Cambrian time a large part of west-central United 
States was a land surface. In middle Cambrian time there began the development 
of an interior sea which finally reached the Rocky Mountain province, where it had 
an irregular shore line about a great series of archipelagoes. From the ancient 
crystalline rocks of these shores waves and streams gathered and concentrated 
sands and pebbles, which were deposited as a widespread sheet of sandstone and 
conglomerate on seabeaches, partly in shallow waters offshore and partly in estu- 
aries. In some areas there are exposures in which these sediments, containing 
much local material, may be seen abutting against the irregular surface of the crys- 
talline rocks which formed these shores. The central portion of the Black Hills 
was probably an island in the earlier stages of this period, and, as Mr. Emmons 
has shown, the Laramie Range and the Rocky Mountain Front Range were for a 
long period highlands rising out of the Cambrian sea. In the northern portion of 
the province thick masses of deposits accumulated as submergence progressed in 
middle Cambrian time, but it is not known that this deposition extended into 
eastern Colorado. The scanty deposits of later Cambrian age appearing near 
Manitou and Canyon indicate that the waters finally reached the line of the present 
Rocky Mountain Front Range. As these deposits lie in embayments which prob- 
ably were connected with wider areas of open waters, doubtless there was a wide 
area of later Cambrian deposition eastward under Colorado. 

a Hills, R. C, Description of the Walsenburg quadrangle: Geologic Atlas U. S., folio 68, U. S. Geol. Survey, 1900, p. 1. 



46 ARKANSAS VALLEY IN EASTERN COLORADO. 

Ordovician. — Apparentlj'^ the submergence above described continued with 
similar shore hnes through a portion of Ordovician time, for the later Cambrian 
and earlier Ordovician appear to have about the same limits in the exposures in the 
embayments above mentioned. Doubtless to the east of the Rocky Mountain 
fr6nt there was extensive deposition of the lime sediments such as appear in the 
outcrops, and these may attain considerable thickness under eastern Colorado. 
Except in the embayments, the western shore apparently was located east of the 
extensive "Red Beds "-granite overlap. Perhaps the deposits originally extended 
farther west all along the slopes and were removed by later erosion along the steeper 
shores, leaving remnants or projections in the embayments where the erosive forces 
were less vigorous. 

Silurian-Devonian. — From the close of the Ordovician to the time of the early 
Carboniferous sea the uplifts along the western margin of the Great Plains region 
present no geologic record, the Silurian and Devonian being absent throughout. 
This is probably because there was an extensive but very shallow sea, or land so 
low as to leave no noticeable evidence of erosion. Whether it remained land or sea, 
or alternated from one to the other condition, the region shows no evidence of hav- 
ing undergone any considerable uplift or depression until early in Carboniferous 
time, when there was a decided subsidence, which established relatively deep water 
. and marine conditions generally throughout the region. 

Carboniferous sea. — Under the marine conditions of the early Carboniferous 
there were laid down calcareous sediments, which are now represented by several 
hundred feet of nearly pure limestone, exhibited in the Black Hills, the Bighorn 
Mountains, and the Hartville uplift, and, with less thickness, in isolated areas in 
Colorado. Along the Rocky Mountain front in Colorado the Millsap "timestone, 
representing the Lower Carboniferous, appears at only a few points, apparently in 
estuaries which extend west of a general shore line now buried under the Upper Car- 
boniferous sediments by the overlap of the latter on the crystalline rocks. In the later 
part of earlier Carboniferous time there was uplift, resulting in shallower waters, with 
sediments of mixed limy and sandy nature in some portions of the region to the north- 
west, while along the Front Range, in Colorado, there was recession of the shore lines 
to an unknown distance eastward, a condition indicated by pronounced unconformity 
at the top of the Millsap limestone. 

During Permsylvanian or later Carboniferous times the shore line extended 
along the foot of the present Rocky Mountain Front Range, and the coarse red sedi- 
ments of the " Red Beds " were laid down in part on a granite floor. There were strong 
currents, and possibly at some stages estuaries and swift-flowing streams. Shallow 
waters extended far to the east, and especially to the southeast, but finally the depth 
increased somewhat in these directions, the coarse' deposits giving place in greater 
part to limestones and shales. Limestones also appear to the north in Wj^oming and 
southward toward New Mexico, so that the principal area of deposition of the coarser 
shore deposits was between Huerfano River and the Wyoming line. In Permian 
time there was a shallow basin which extended across the western portion of the 
Central Plains region and far to the northwest. In this basin were laid down the 
great mass of red shales of the Chugwater formation, or upper "Red Beds," with 
their extensive interbedded deposits of gypsum, presumably products of an arid cli- 



U. S. GEOLOGICAL SURVEY 
.1 



PROFESSIONAL PAPER NO. 52 PL. XXII 




MAP AND CROSS SECTIONS SHOWING RELATIONS OF "DAKOTA" AND ASSOCIATED 
FORMATIONS ON EAST SIDE OF WEST MOUNTAINS, COLORADO. 



GEOLOGIC HISTORY. 47 

mate. The sandy clay of this forniation accumulated in thin layers to a thickness 
of 500 to 1,000 feet in Wyoming and the Black Hills, but is much thinner in Colorado. 
There is such uniformity of the deep-red tint that it is undoubtedly the original color, 
and this color is present not only throughout practically the entire outcrop of the 
forniation, but also throughout its entire thickness, as is shown by deep borings. It 
is, therefore, not due to later or surface oxidation. This deposition of red mud was 
interrupted from time to time by chemical precipitation of comparatively pure gyp- 
sum in beds ranging in thickness from a few inches to 30 feet, often free from mechan- 
ical sediment. It is apparent that these beds are the products of evaporation while 
mechanical sedimentation was temporarily suspended, a condition indicative of 
greatly diminished rainfall ; otherwise it is difficult to understand their nearly general 
purity. Most of the red deposits were laid down in shallow water, so that there 
must have been subsidence which kept pace with deposition most of the time. 

To the southeast, in Kansas and Oklahoma, there was deposited simultaneously 
with the gypsiferous "Red Beds" a part, at least, of the dark shales into which they 
merge. These shales, which are of Permian age, contain thick deposits of salt and 
scattered deposits of gypsum at various horizons. Apparentlj^ also to the southeast 
some of the lowest " Red Beds" deposits are represented by limestones of the lower 
members of the Permian, the products of deeper marine waters. "^Yhether this depo- 
sition of the " Red Beds " extended into or through Triassic times in the Central Plains 
region is not known, but evidentl}' it was terminated by uplift which brought the 
region above water. Probably this condition extended through the latter part, if not 
all, of the Triassic and through Jurassic time, during which there was no deposition 
and probably some slight erosion. South of the vicinity of the Wyoming line this 
interval is represented by the general hiatus between the upper " Red Beds " and the 
Morrison deposits. 

Cretaceous. — East of the Rocky Mountains Morrison sedimentation was in a 
long, relatively narrow trough extending along the west side of the Great Plains. 
This trough was occupied by a shallow bod}^ of fresh water which deposited mixtures 
of clay and fine sand, with thin, irregular bodies of coarser sand deposited by streams 
or along shores and with occasional thin beds of impure carbonate of lime. Huge 
saurians were numerous, as shown by the frequent occurrence of their remains in 
the deposits, although it is possible that this abundance is due mainly to increased 
mortality or more favorable conditions of preservation, or both. 

Morrison time was succeeded abruptly by a change to conditions under which 
coarse-grained, cross-bedded, massive Dakota-Lakota sandstones were deposited. 
Although the deposits change abruptly and there was local channeling of the surface 
of the soft Morrison deposits, the erosion appears to be of remarkably small amount 
and no more than would be expected to result from the strong currents bearing 
coarse sands and pebbles. 

It is believed that there was no great uplift-erosion interval following Morrison 
deposition, for if there had been the soft deposits would have been widely removed. 
As it is the Dakota-Lakota sandstones lie on a uniform series of Morrison sedi- 
ments from Montana to New Mexico and Oklahoma. It is a significant fact also in 
this connection that some of the saurians of Morrison time appear to have continued 
into the next epoch. In the region in southeast Colorado, western Kansas, and a 



48 ARKANSAS VALLEY IN EASTERN COLORADO. 

wide area southward, where the Morrison formation is absent, there probablj'^ was 
dry land during Morrison time, but there may have been deposition of more or less 
Morrison sediments which were afterwards removed by erosion in an early Creta- 
ceous uplift. Marine conditions followed, during which the great Comanche series 
was accumulated. Farther north and west in Comanche times there was at first a 
land surface and then shallow waters, in which were deposited the sands now con- 
stituting the Lakota sandstone. This was followed by deeper waters, with wide- 
spread deposition of the material of the fire clay (Fuson) separating the Lakota and 
Dakota sandstones. Next came a recurrence to conditions similar to those of 
Lakota time, and the Dakota sands were laid down, marking the beginning of 
later Cretaceous time. The Lakota and Dakota sands were derived from various 
soiu"ces, probably to the west, and spread by strong currents in two thick deposits 
separated by the interval of invasion of deeper water and cessation of strong cur- 
rents, in which the widespread intervening fire clay was laid down. The sandstones 
overlap the granites in portions of the region — for instance, southwest of Pueblo and 
north of Canyon — and there are other places in the granite area from which the sand- 
stones evidently have been but recently removed. These features indicate the posi- 
tion of a portion of the shore lines at least. The extent of the Lakota, as separated 
from the Dakota, not having been ascertained, except that both are present in 
the Black Hills region and that the Lakota is surely absent in east Nebraska and east 
Kansas, their relative areas of deposition can not yet be indicated. The vast extent 
of this coarse sandstone formation is a wonderful feature, and it is difficult to picture 
the conditions under which it accumulated. The writer formerly thought that there 
might have been a shore line progressing gradually westward, with coarse deposits 
near shore and fine deposits in the deepening waters east, so that the "Dakota" 
sandstone in western Kansas, for instance, might be represented by shales in central 
Kansas, but as the very characteristic Benton stratigraphy and the " Dakota "- 
Benton relations are so uniform over the entire area this hypothesis is untenable. 

Following the deposition of this great sheet of sandy sediments there was a 
rapid change to clay deposition, of which the first representative is Benton shale, 
a formation even more extensive than the underlying "Dakota" sandstone. This 
represents the later Cretaceous submergence, in which marine conditions prevailed, 
and it continued until several thousand feet of clays were deposited, during the 
Benton, the Niobrara, and the Pierre epochs. In Benton times there were occa- 
sional deposits of sand and one thin, but very widespread, deposit of carbonate of 
lime — the Greenhorn limestone — near the middle of the Benton sediments. The 
shale of the Benton is followed by several hundred feet of impure chalk, now con- 
stituting the Niobrara formation, and this in turn by many hundred feet of Pierre 
shale, which thickens rapidly to the west, attaining 1,200 feet or more in western 
South Dakota and over 7,000 (?) feet adjacent to t'he Rocky Mountains in a limited 
area west of Denver. 

The retreat of the Cretaceous sea, which corresponds with the Fox Hills epoch, 
resulted in extensive bodies of brackish waters, which spread sands over the clay 
beds, and then of fresh waters, which deposited the sands, clays, and marsh material 
of the Laramie. Apparently these last-mentioned formations were not laid down 
much east of longitude 101°, for they thin rapidly to the east, although, as we do not 
know the extent of post-Laramie erosion, their former limits can only be conjectured. 



GEOLOGIC HISTORY. 49 

Post-Laramie conditions. — There was extensive uplift in the Rocky Mountain 
province following Laramie deposition. This fact is clearly indicated in some areas 
in the mountains, where the next succeeding deposits lie on an eroded surface 
having the general outlines of the present configuration, a relation which shows 
that some of the mountain uplifts were truncated and the larger outlines of 
topography established by earlier Eocene time. This erosion was largely effected 
by streams which had strong declivities due to the uplifts. The earliest deposits 
were the coarse beds of the Arapahoe and Poison Creek formations, which mark 
one subperiod of uplift and deposition, the Denver, Cuchara, and Huerfano forma- 
tions marking another. Later, after the outlines of the great mountain ranges to 
the north and west had been carved, there was a long period in which streams of 
moderate declivity flowed across the central Great Plains region. These, with 
frequently varying channels and extensive local lakes, due to damming and the 
sluggish flow of the waters, laid down the widespread mantle of the Oligocene, or 
White River and Monument Creek deposits. These began with the sands, which 
show clearly the course of old currents by channels filled with coarse sandstone and 
areas of slack water and overflow in which fuller's earth and other clays were laid 
down. The area of deposition of this series extended across eastern Colorado and 
Wyoming and western Nebraska and South Dakota, and probably also farther 
north, for the deposits have been found in western Canada. Doubtless the original 
extent was much wider than the area in which we now find the formation, for 
much has been removed by erosion. 

At the beginning of Miocene time the general conditions had not changed 
materially, but doubtless for a while an extensive land surface existed in the Central 
Plains area. To the north the stream channels extended across this surface, and 
running water laid down a widespread sheet of sands derived from the mountains 
to the west. Probably the streams were aided, to a minor extent, by winds. The 
streams of this time shifted their courses across the plains, spreading the debris 
from the mountains in a sheet which in, some portions of the area attained a thick- 
ness of 1,000 feet — a flat alluvial fan of wonderful extent. This is the Arikaree 
formation, which buried some of the lower ranges of mountains to the north. It was 
followed by uplift, and by erosion which removed the Arikaree and part^ of the 
underlpng formations from the south and the east, leaving the thickest mass of the 
deposit in western Nebraska and eastern Wyoming. Probably, however, it never was 
thick nor widespread to the south, erosion predominating in that part of the area 
during deposition to the north. Next came the epoch in which the streams began 
depositing the thin mantles of sands of the Ogalalla-Nussbaum and other late Plio- 
cene formations, especially in southern Colorado, southern Nebraska, Kansas, and 
regions farther south. At this time deposition appears to have been mainly in the 
south, erosion probably predominating farther north. 

These alternating conditions of later Tertiary deposition and erosion, first in 
the north and next in the south, were undoubtedly determined by differential uplift, 
the uplifted region suffering erosion and the depressed or stationar}^ region receiving 
deposits from streams which did not have sufficient declivit}'^ to carry off their loads. 
This condition also is a feature of the semiarid climate of the Great Plains, the 

4551— No. 52—06 4 



50 ARKANSAS VALLEY IN EASTERN COLORADO. 

mountain torrents and resulting vigorous erosion furnishing large amounts of debris, 
which the streams of low declivity and constantly diminishing volume were unable 
to carry to the sea. Even if such a region is traversed by valleys cut during a time 
of uplift or increased rainfall, when cutting ceases these valleys are soon filled by 
sediments, and when they are full the streams, at times of freshet and to a less 
extent in the dry portion of the year, shift their courses so as finally to spread a 
wide mantle of deposits over the entire area in which there is sluggish drainage. 

Quaternary. — During early Quaternary time there was uplift and floods from 
increased precipitation, causing widespread denudation and trenching 'of the pre- 
ceding deposits. The smooth, high plain mantled by the Ogalalla-Nussbaum forma- 
tions, which originally extended to the foot of the mountains, was deeply trenched 
and widely removed, especially along the Arkansas and Platte valleys. These were 
wide and very shallow at the end of Tertiary time, when the present drainage system 
was outlined, but they were cut deeply in the succeeding uplift and the smaller side 
valleys were then developed. The two large streams east of the mountains have 
since cut their valleys to a low gradient and in times of flood build up their flood 
plains, but the smaller streams are still cutting. 

UNDERGROUND WATERS. 

In the thick series of sedimentary rocks underlying southeastern Colorado are 
several deposits which contain water. The principal water-bearing formation is 
the "Dakota" sandstone, but waters also occur extensively in the alluvial deposits 
along the valleys, in the sands and gravels mantling parts of the upland east of the 
mountains, and in the sandstones of the Fox Hills, Laramie, and overlying forma- 
tions. Smaller amounts, mostly of bad quality, occur in the "Red Beds." 

"DAKOTA" SANDSTONE WATERS. 
GENERAL CONDITIONS. 

Throughout its wide extent in the Great Plains region the "Dakota" and asso- 
ciated sandstones contain water, usually of good quality and under considerable 
pressure. This water passes into the sandstones in their elevated outcrop zone 
along the foot of the mountains and in some of the highlands to the south, and flows 
slowly eastward through the permeable sandstone, in most cases finally escaping 
in springs in the areas of low-level, outcrop eastward. In the greater part of their 
area the sandstones lie beneath a mass of impervious shales, which in central-east- 
ern Colorado attain a thickness of several thousand feet. The general structural 
relations of the formation are shown in detail in the cross sections of PL VII. 

As the waters pass underground in high areas they have considerable pressure, 
or "head," under the impermeable strata in the lower lands. In parts of eastern 
Colorado pressures of 20 to 60 pounds are sometimes presented, which can be ex- 
plained only by the hydrostatic influence of a column of water extending to a high 
altitude in the region west. If it were not for the outflow of the water to the east 
and south the initial head which the waters derive from the high altitude of the 
intake zone would continue under the entire region, but owing to this leakage the 
head is not maintained, and there is a gradual diminution to the east, known as 







o 

r 






o 



iUg_ 







u 
ei 

Q 

_l 

o 
o 
o 



LLJ 

Z) 

a. 



O 



> 
Id 



cc 



111 

u. 
o 



o 

I- 



5 

o 

I 



o 

uJ 



UNDEEGEOUND WATEES. 



51 



Pierre 



Niobrara 



Benton. 



^^I^^t^I^^F^^^^^^^^ -20OO 



3-1200 



'Dakota" .. 



Morrison 



"Red Beds' 




Feet 

240 O 



Dark shale with lime- 
stone masses. 



Dark shale with rusty 
I GO O concretions. 



Dark shale. 



800 



s-400 



Shales with thin lime- 
stones. 



White limestone. 

Dark shales; sandstone 
generally at the top. 

Gray limestone. 
Dark shale. 

Sandstone. 
Fire clay. 

Sandstone. 

Clays, light colored. 



Red sandstone and 
shale. 



Fig. 1.— General section showing thickness of strata overlying the " Dakota " sandstone in the Arkansas Valley. 



52 



AEKANSAS VALLEY IN EASTERN COLOBADO. 



"hydrostatic grade," a slope sustained by the friction of the water in its passage 
through the strata. In fig. 2 is shown a simple apparatus which illustrates the gen- 
eral conditions. 

Another factor which undoubtedly somewhat influences the hydrostatic grade 
in the Great Plains region is a certain but unknown amount of general leakage 
through the so-called impermeable strata, all of which permit the passage of an 
appreciable proportion of water, especially when under great pressure. From the 
altitudes of outcrops of this sandstone and pressures observed in many wells the 
lines in PI. XXVIII have been constructed to indicate the observed and probable 
head of the artesian waters. In areas of flow the pressure in pounds at any point 
may be ascertained by subtracting the altitude of the land from the altitude of 
head and dividing by 2.3 (the height in feet of a column of water 1 inch square 
weighing 1 pound) . In areas too high for flow the depth to the point to which the 
water may be expected to rise may be found by subtracting the altitude of head 
from the altitude of the land. The latter is shown by the brown lines in Pis. VI 
and XXV. 




I 



I 



Fig. 2. — Diagram of apparatus for illustrating the declivity of head of liquids flowing from a reservoir. 

portions represent water. 



The shaded 



FLOWING WELLS. 

Rocky Ford. — Nearly all of the flowing wells in the Arkansas Valley derive 
their water from the "Dakota" sandstone. There are several artesian wells at 
Rocky Ford which furnish large supplies of excellent water under considerable 
pressure. The depths vary from 767 to 1,033 feet. Wells Nos. 1 and 2 have a 
diameter of 7f inches and a flow of over 100 gallons per minute, with sufficient head 
to rise 80 feet or more above the surface. One of these is shown in PL XXIV, B. 
The materials penetrated by these wells are indicated in the following record: 



Surface materials. 
Shale 



Record of artesian well at Rocky Ford, Colo. 
\ 



» Feet. 

0-40 

40--250 

Limestone with salty water at its top 250-290 

Shale 290-605 

" Talc vein" _ . _ 605-608 

Shale _ 608-690 

First sandstone ( Dakota) with a flow of soft water 690-790 

These wells begin in the lower part of the Apishapa formation, pass through 
the characteristic limestone bed at the base of the Timpas formation from 250 to 



OTERO COUNTY WELLS. 53 

290 feet, and penetrate 400 feet of the Benton formation. The latter contains the 
characteristic 3-foot bed of "talc" 100 feet above the top of the "Dakota" sand- 
stone. 

An 845-foot well at Wyckoff Park, near Rocky Ford, has a 4-inch bore and a 
flow of 115 gallons a minute. 

The well of the American Beet Svigar Company, sunk by C. H. McVaj^ in 1901, 
had the following record: 



Record of artesian well of sugar company at EocTcy Ford, Colo. 

Feet. 

Surface materials 0-30 

Gray shale 30-265 

Limestone 265-312 

Black shale, with salt water at 382 feet 312-700 

"Dakota" sandstone 700-806§ 

At 793 feet this boring yielded a 50-gallon flow, which increased to 80 gallons 
at the bottom. 

Manzanola. — At Manzanola there is an artesian well which was sunk by the 
town company. Its depth is 1,113 feet, with a diameter of 7f inches, and it yields 
35 to 40 gallons a minute under a pressure of about 55 pounds. The materials 
penetrated by this well are as follows: , 

Record of first artesian well at Manzanola, Colo. ; 

Feet. 

Surface materials 0- 38 

Shale 38- 598 

Limestone 598- 633 

Shale - - 633- 933 

"Talc vein" 933- 936 

Shale 936-1,033 

First sandstone (Dakota) 1, 03.3-1, 113 

The record shows beds of the Apishapa formation, with the typical Timpas 
limestone at a depth of 598 to 633 feet, underlain by 400 feet of the Benton group. 
The latter contains the very distinct bed of hard shale at 933 to 936 feet which the 
well drillers designate the "talc vein," and have recognized in many borings in the 
Arkansas Valley. 

In 1903 a well was sunk at Manzanola for the purpose of testing the forma- 
tions below the "Red Beds" for oil and gas. A depth of 2,110 feet was attained 
without satisfactory results. The pipe has been pulled and the well abandoned. 
The following record has been given: 

Record of deep having at Manzanola, Colo. 

Feet. 

Loam 0- 50 

Limestone and shales (Niobrara and Benton groups) 50-1, 050 

Sandstone; first "Dakota" artesian flow, 50 gallons 1, 050-1, 139 

Shales .' 1,139-1,239 

Sandstone; second "Dakota" artesian flow, 10 gallons 1, 239-1, 375 

Gray clays (Morrison formation) 1 , 375-1, 655 

" Red Beds," with several water-bearing strata 1, 655-2, 110 



54 ARKANSAS VALLEY ITST EASTEElSr COLORADO. 

The water in the "Red Beds" was too impure for use, and had only pressure 
enough to rise to 700 feet below the surface. 

Fowler. — The first flowing well below Pueblo is about 2 miles east of Fowler, 
on the Atchison, Topeka and Santa Fe Railway. It has a depth of 1,372 feet, at 
which it obtains a flow of soft water from the upper sandstone of the "Dakota" at 
the rate of about one-half gallon a minute. The record of this well is as follows : 

Record of artesian well near Fowler, Colo. 

Feet. 

Surface materials 0- 40 

Shale 40- 825 

Limestone 825- 875 

Shale '. 875-1,270 

First " Dakota " sandstone '. 1, 270-1, 372 

This boring begins on the Pierre shale, passes through the Apishapa and Tim- 
pas formations of the Niobrara, the limestone at 825 to 875 feet being the character- 
istic bed at the base of the Timpas, and penetrates 395 feet of the Benton formation 
to the top of the "Dakota" sandstone. 

La Junta. — In this town there are several wells, formerly flowing, which yield 
soft water that is extensively used by the railroad company and in part for munici- 
pal supply. The principal supply is in the second bed of sandstone of the "Da- 
kota" formation, which is entered at a depth of 555 feet. Most of the wells are 
between 405 and 439 feet deep. A boring by the railroad company passed through 
both sandstones of the ' ' Dakota ' ' formation and the underlying shales and sandstone 
into the "Red Beds," which it penetrated at 1,050 to 1,150 feet. The record of 
this boring is as follows : 

Record of deep boring at La Junta, Colo. 

Feet. 

Surface materials 0- 37 

Gravel 37- 48 

Shale 48- 230 

"Talc" '..: 230- 235 

Shale and light shale 235- 340 

" Dakota " sandstone, soft water 340- 423 

Black shale , 423- 451 

Gray sandstone 451- 545 

Black shale .,. 545- 555 

Sandstone ; soft water, flows 555- 605 

Shale 605- 950 

Sandstone; water, no flow 950-1, 050 

Red and variegated shale 1, 050-1, 150 

This well was plugged at 700 feet and obtains its principal supply of water from 
the second bed of sandstone in the "Dakota" formation at 550 to 605 feet. The 
original flow at 420 feet was 35 gallons a minute, but vigorous pumping has lowered 
the water level many feet and the water is now forced out by air lift. The wells at 
La Junta begin in the Timpas formation, but soon pass into the Benton shale, 
reaching the characteristic "talc vein" at 230 feet and the top of the "Dakota" 
formation at 340 feet. This formation presents an alternation of heavy beds of 
sandstone with intercalated shales, and from the record above given may extend to 



U. S. GEOLOGICAL SURVEY 



PROFESSIONAL PAPER NO. 52 PL. XXIV 




A. ARTESIAN WELL ON RIDGE SOUTH OF LA JUNTA, COLO. 
Depth 750 feet to Dakota sandstone. Not flowing at present. 




B. FLOWING WELL AT ROCKY FORD. COLO. 
Flows from a depth of 790 feet from Dakota sandstone. 



WELLS NEAR LA JUNTA. 55 

a depth of 605 feet. The underlying shales and sandy beds are those which 
outcrop on Purgatory River, 25 miles south of La Junta, Ipng on the sandstones 
and shales of the "Red Beds," which were entered at a depth of 980 feet in the deep 
boring near La Junta. 

Two other wells of the railroad company are 420 and 439 feet deep and are 
pumped by air lift. A well in the McNeen brickyard, with a depth of 405 feet, 
obtained a small flow at 395 feet, which increased to 8 gallons a minute at 405 feet. 
Its diameter is 4 J -inches. The well at the flouring mill in La Junta is 425 feet 
deep and flowed 30 to 45 gallons a minute until other wells in the neighborhood were 
pumped, when the flow ceased. It is now pumped at the rate of 30 gallons a minute, 
but this is not its full capacity. An analysis of the water is given on pages 80, 81. 

A well on the hill in the southern part of the town is about 150 feet above the 
railroad depot, and its depth is 750 (or 766) feet. When completed, it flowed 25 
gallons a minute. Now the water rises only to the surface, owing to partial filling 
with sand and possibly to a general reduction of the water level in the vicinity by 
the several wells near the depot. A view of this well is given in PI. XXIV, A. 

In 1902 a company was organized to sink a deep well 2 J miles south of La Junta 
to test the "Red Beds" and their underlying formations for gas or oil. A depth of 
1,703 feet was reached without obtaining either of these products. Although a 
number of beds of limestone were penetrated in the lower portion of the boring, it is 
probable that they are a part of the "Red Beds" series. The following record has 
been supplied: 

Record of deep boring south of La Junta, Colo. 

Feet. 

Soft gray limestone 0- 50 

Rusty limestone at base of N iobrara 50- 60 

Dark shales of Benton group 60- 440 

Soft sandstone with artesian flow; first " Dakota " 440- 504 

Shales 504- 584 

Soft sandstone ; artesian flow ; second " Dakota " 584- 700 

Gray and greenish-gray shales with water at 820 to 120 and 860 to 100 feet (Morrison formation) . . 700- 980 

" Red Beds " with water at intervals which rose to within 200 feet of the surface 980-1, 703 

Some samples forwarded to Washington are as follows : 

Samples of borings from La Junta, Colo. 

Feet. 

Sand and fine-grained sandstone of gray color, with some limestone layers and reddish sandstone. . 1, 230-1, 290 

Red shale, with some limestone layers 1, 300-1, 500 

Red shale, with some limestone fragments 1, 535 

White sand 1, 600 

Red shale, with some limestone fragments .-. 1, 612 

Gray limestone and red shale 1, 660 

Red shale and gray limestone 1, 703 

The Lenox well, in SE. | sec. 2, T. 24 S., R. 56 W., 5 miles west of La Junta, has 
a depth of 740 feet, a diameter of 7| inches, and yields a flow of 12 gallons a minute. 
The well began in Timpas limestone, 40 feet above its base, passed through 400 feet 
of Carlile, Greenhorn, and Graneros beds to the top of the "Dakota" sandstone at 
440 feet and penetrated the two sandstones of the " Dakota " for 300 feet. In the 
northeast quarter of the same section, on J. E. Gauger's ranch, there is a similar 



56 ARKANSAS VALLEY IN EASTERN COLORADO. 



well flowing 15 gallons a niinute. According to Mr. McVay, the driller, the beds are 
at slightly lower levels, indicating a dip of 27 feet to the mile in that direction. 

Holhrook. — At this place, which is 9 miles due north of La Junta, in SE. \ sec. 27, 
T. 22 S., R. 55 W., there is a well 661 feet deep, which flows about 100 gallons a 
minute. The head of the water is sufficient to raise it 80 feet, or probably much 
more, above the surface, and the flow is about 50 gallons a minute from a 3-inch 
pipe extending to the bottom. The water is soft. No record was obtainable, but it 
is stated that the boring passed through 155 feet of limestone, 385 feet of Benton 
shale with some limestone at a depth of 350 feet, and penetrated 110 feet into the 
"Dakota" sandstone. In the next township east are two shallower wells which 
have flows from the sandstone. 

Timpas. — The following report of the well at this place has been furnished: 

Record of boring at Timpas, Colo. 

Feet. 

Loam J 0-37 

Dry gravel 37- 40 

Shale 40- 85 

Limestone (basal Timpas) , some water 85-137 

Shale, with " talc vein " at 440 to 443 feet =398 feet of Benton 137-538 

Sandstone (" Dakota ") ; poor water at 544 feet, rising to 50 feet; 2-gallon flow at 570 feet 538-580 

Shale 580-605 

Sandstone ; poor water 605-650 

Shale :• 650-656 

Gray sandstone 656-716 

Sandstone (" Dakota '') ; 20-gallon flow at 755 feet 716-790 

Red shale (Morrison) 790-795 

The water which flowed at 755 feet was too highly mineralized to be usable in 
boilers, so that the boring is regarded as a failure. The water flowed into a tank 
27 feet above the ground. 

Ayer. — This is a siding on the Atchison, Topeka and Santa Fe Railway, 6 miles 
southwest of Timpas, and the record of the well is as follows : 

Record of boring at Ayer, Otero County, Colo. 

Feet. 

Surface material _ 0-40 

Gravel 40-43 

Gray limestone 43- 80 

Black shale, with "talc vein" 147 to 150 feet. 80-249 

Sandstone (Dakota) ; soft water _ 249-272 

Shale 272-280 

Gray sandstone ; dry 280-287 

Black shale 287-293 

Sandstone; poor water; 25-gallon flow near bottom; 3-gallon flow at 311 feet 293-343 

The water is of unsatisfactory quality, containing 18 grains of sulphate of lime 
to the gallon. 

Bloom {Iron Sj>rings) . — The boring at this place, sunk for the Santa Fe Railway, 
had a depth of 1,162 feet and yielded a flow of 5 gallons a minute, with a pressure 
sufficient to raise it 50 feet or more above the surface, but it was abandoned, as the 
water was too hard for use in locomotives. The following record is furnished : 



U.S. GEOLOGICAL SURVEY 



PROFESSIONAL PAPER NO. 52 PL. XXVI 



105° 



104; 



103 



102' 







EXPLANATION 



AreaTinderlaia hy 
"t) alcota" s ands tones 



104" 



103 



102' 



MAP SHOWING STRUCTURE OF 
"DAKOTA" SANDSTONE IN EASTERN COLORADO 

BY N.H.DARTON 
1905 

Scale 

20 10 o 20 40 60:txiiles 



AJ^oen4Co BaliimorE 



Black contours liave 10 OO-footiatervalSjlDrokBn lines hypoQietical 



WELLS AT BLOOM AND LAS ANIMAS. 57 

Record of boring at Bloom siding, Otero County, Colo. 

Feet. 

Clay _ 0- 25 

Gravel 25 31 

Shale, with bad water at 76 feet _ 31- 87 

Gray shale 87- 154 

Gray sandstone 154- 168 

Black shale _ _ 168- 170 

Sandstone, brown above ; poor water 170- 229 

Shale 229- 233 

Sandstone ; 5-gallon flow of water at 240 feet 233- 244 

Hard sandstone '. 244r- 255 

Sandstone; second water at top, first flows 3 to 4 gallons; another flow at 385 feet 255- 400 

Red shale (Morrison) : 400- 450 

White sandstone (Morrison) -" 450- 455 

Red shale 455- 475 

Red sandstone _ 475- 575 

Light-gray shale ." _ 575- 695 

Light-brown sandstone 695- 815 

Dark-red sandstone 815- 880 

Red sandstone _ _ 880- 965 

Red shale ". 965- 985 

Red sandstone 985- 995 

"Marble " 995-1, 000 

Red shale 1,000-1,007 

Red sandstone ; water rose 450 feet ; quality bad .' 1, 007-1, 020 

White "limestone" 1,020-1,025 

Red sandstone 1, 025-1, 085 

"Limestone" 1, 085-1, 087 

Red sandstone _ 1, 087-1, 125 

"Limestone " _ 1, 125-1, 128 

Pink sandstone; water rose 80 feet. 1, 128-1, 133 

Red sandstone 1, 133-1, 140 

Red shale 1, 140-1, 145 

White sandstone; water rose 350 feet , ._ 1, 145-1, 155 

Red shale 1, 155-1, 162 

The boring begins near the base of the Graneros shale of the Benton group 
and passes through various members of the "Dakota" sandstone series into the 
"Red Beds." It was located on the axis of the anticline extending from the south. 
It is difficult to understand why a large supply of water was not obtained from 
the various sandstones which were reported. 

Las Animas. — The railroad well at Las Animas is relatively shallow, obtaining 
a 20-gallon flow of excellent water from the second sandstone in the "Dakota" 
formation at a depth of 330 feet. The following record is reported: 



Record of artesian well at Las Animas, Colo. 

Feet. 

Surface materials 0-36 

Shale- 36- 90 

Sandstone; water at a depth of 90 feet, rising to —10 feet _ 90-195 

Shale ._ - : _ 195-240 

Sandstone; flow at 330 feet 240-333 

Shale 333-360 



58 ARKANSAS VALLEY IN EASTERN COLORADO. 

This well begins in the lower part of the Benton shale and reaches the " Dakota" 
sandstone at a depth of 90 feet, as this formation rises rapidly east of La Junta. 
The second bed of sandstone in the "Dakota" formation begins at 230 feet, with 
the usual intervening mass of shale. (See PI. XXIII.) Other wells in Las Animas 
have depths of 250 and 267 feet and flow 17 and 5 gallons, respectively. A well 
sunk in 1904 on the Cooper place, a mile north of Las Animas, has a depth of 316 
feet and a flow of 10 gallons a minute from a depth of 285 feet. It is cased with 
5f-inch tubing. The pressure is sufficient, it is said, to lift the water 20 feet above 
the surface.^ The following record has been furnished by John Baugh, the driller: 



Record of Cooper well, 1 mile north of Las Animas, Colo. 

Feet. 

Surface materials ^ 0-10 

Sand, vnth water 10- 30 

Black, sandy shale .30- 60 

Black shale 60-70 

Sandstone (Dakota) , with water to —6 feet 70-170 

Shale, with sandstone layers 170-266 

Sandstone (second "Dakota"), with main flow at 285 feet 266-316 

Twelve miles northeast of Las Animas is the well which was sunk in 1881 by 
the Government under direction of the Department of Agriculture. It was known 
as well No. 1, and is located 7 miles northeast of Fort Lyon. It had a depth of 
815 feet, but obtained only a small amount of water from a depth of 430 feet, which, 
flowed at the surface at a rate reported by some persons as 2 gallons a minute, and 
by others as only 3 gallons an hour. The head was stated to be just sufficient to 
raise the water 10 feet above the surface of the ground. This boring cost $18,353; 
the record is as follows: 

Record ofioring at Fori Lyon, Colo. 

Feet. 

Sand, gravel, and quicksand 0-74 

Soft, blue clay ! 74- 80 

Blue shale ' 80- 86 

Gray sandstone ,. 86-116 

Dark shales 116-120 

Streaked sandstone 120-140 

Gray, clean grit 140-150 

Black , sandy shale. , 150-180 

Mottled, gray sandstone 1 80-190 

Mica sandstone 190-200 

Mixed sandy shale, light, very soft 200-225 

Mixed sandy shale, dark, very soft 225-250 

Black, variegated shale, very soft 250-275 

Mottled purple shale, soft ' 275-300 

Gray shale, soft 300-320 

Mottled shales, soft , 320-340 

Black shale, soft.... 340-344 

Graj' sandstone 344—355 

Coarse sandstone 355-.368 

Gra}' sandstone 368-382 

Greenish clay — 382-386 

Marl 386-396 

Green and red sandstone, soft 396-439 



ARTESIAN WELLS. 59 

Feet. 

Dark-red shale 439-445 

Rusty gray sandstone 445-450 

Green shale 450-460 

Green and red shale, soft ,. 460-500 

Gray sandstone _ 500-520 

Compact gray shale 520-550 

Hard shales : 550-570 

Fine, red sandstone 570-590 

Coarse, red sandstone 590-630 

Hard, red sandstone ; some gypsum 630-650 

Spotted sandstone 650-662 

Mixed sandstones 662-703 

Red sandstone, massive 703-751 

Soft, red sandstone ^ 751-783 

Spotted red sandstone 783-815 

The Marlaman well on Horse Creek, 12 miles northwest of Las Animas, has a 
depth of 493 feet, and. a 7-gallon flow from the second "Dakota" sandstone. The 
following record was furnished: 

Record of artesian well, 12 miles northwest of Las Animas. 

Teet. 

Surface materials 0-30 

Limestone and shale 30-230 

Dakota sandstone, small flow 230-330 

Shale and sandstone 330-443 

Second " Dakota " sandstone 443-493 

Plum Creek. — At the Blackwell ranch, on Plum Creek, about 20 miles south of 
Granada, there is a small artesian well which obtains its flow from the "Dakota" 
sandstone at a depth of 155J feet. It is in sec. 1, T. 26 S., R. 44 W. The head 
was found more than sufficient to raise the water to the top of the tubing, 46 
feet above the ground. The volume is 18 gallons or more a minute. This well is 
important as indicating that artesian waters may be expected in the central and 
east-central portions of the county, at some distance south of the Arkansas Valley. 
Much of this region is occupied by the Greenhorn limestone in the middle of the 
Benton group, so that ordinarily about 250 feet of shales would have to be 
passed through to reach the top of the "Dakota" sandstone, and this formation 
penetrated for a hundred feet or more to obtain a water supply. 

Puehlo. — The first deep well in the Arkansas Valley was a boring for petroleum 
made at South Pueblo in 1879. At a depth of 1,166 feet a flow of mineral water 
was obtained, amounting to about 100 gallons a minute. The boring was continued 
to a depth of 1,412 feet, and was cased to a depth of 900 feet with 6-inch casing. 
The well has continued to flow with nearly its original volume and a pressure of 60 
pounds to the square inch. The water is not suitable for domestic use, but is the 
basis for the Clark mineral-spring resort, where it is employed for bathing and medici- 
nal purposes. The record of the well is as follows: 



60 ARKANSA.S VALLEY IN EASTERN COLORADO. 

Record of deep well at Clark's mineral spring, Pueblo, Colo. 

Feet. 

Soil and gravel 0- 34 

Blue shale _ 34- 58 

Black shale _ - . - 58- 630 

Sand rock, white below 630- 690 

Black shale 690- 700 

Soft, coarse sand rock 700- 735 

Black shale 735- 900 

Sand rock _ ' 900- 940 

Black shale 940-1, 030 

Sand rock.... 1,030-1,045 

Soft black shale 1, 045-1, 148 

Sand rock with flow of water 1, 148-1, 180 

Black shale 1,180-1,195 

Coarse sand rock 1, 195-1, 230 

Purple shale 1,230-1,240 

Sand rock 1,240-1,270 

Not given ' ' 1,270-1,400 

Purple shale 1 , 400 

The Colorado Coal and Iron Company has a well on the mesa south of and 
about 100 feet higher than the Clark well. The depth is 1,260 feet, and the flow 
of 20 to 25 gallons a minute is not utilized. An analysis of this water is given on 
pp. 80-81. Another well at Mineral Park in the same vicinity obtains a small flow 
from a depth reported to be 1,150 feet. At the Fariss House, north of the river, in 
Pueblo, a well said to be 1,400 feet deep flows 13 gallons a minute and has a pressure 
of 60 pounds to the square inch. An analysis of this water is given on pp. 80-81. 

At the Grand Hotel in Pueblo is a well 1,219 feet deep and 4^ inches in diameter 
which has a flow of about 20 gallons a minute of mineral water under a pressure of 
50 pounds to the square inch. At 1,050 feet there was a flow of fresh water under 
a pressure of 15 pounds. An analj^sis of the water is given on pp. 80-81. On Columbia 
Heights, a suburb of Pueblo, there is a 789-foot well which found a small flow at 
516 feet, and a second flow at 779 feet — in all about 8 gallons a minute. 

Record of well in sec. 9, T. 21 S., R. 65 W., Columbia Heights, Pueblo, Colo. 

Feet. 

Soil on gravel ' 0- 31 

Shale , : 31- 90 

Limestone 90-105 

Black slate *. 105-516 

Sandstone, with water 516-616 

Black slate 616-779 

Sandstone, second flow 779-789 

In the adjoining section 17 is a well sunk by C. H. Small, which in 1888 had 
a depth of 772 feet and a small flow. It was deepened later to a second flow. The 
water is similar to that of other wells in the Pueblo region, containing a good deal 
of mineral matter. The following record is given : 

Record of artesian well ofC. H. Small, Pueblo, Colo. 

Feet. 

Black soil. 0-12 

Blue shale 12-72 

Limestone ' 72-82 



WELLS NEAR PUEBLO AND FLORENCE. 61 

Feet. 

Black shale , 82-413 

White sandstone _ 413-575 

Red rock 575-7eO 

Gray sandstone 760-772 

On North Pueblo Heights a well was sunk hj a suburban company to a depth 
of 1,820 feet, finding small flows at 1,200 and 1,820 feet. This well is in sec. 12, 
T. 20 S., R. 65 W. A flow of 1^ gallons was reported in 1889. All the Pueblo wells 
. draw their water supply from either the upper or the lower sandstone of the " Dakota " 
formation, but the water is too much mineralized to be of general use. There was 
formerl}" a well known as McLane's, 9 miles west of Pueblo and 4 miles south of 
Arkansas River, on Boggs Flat. It was sunk for oil, but none was found. Water 
was reported at several horizons, but no depths were stated. 

A well on the south side of the river 10 miles west of Pueblo is 795 feet deep 
and has a 30-gallon flow. Sandstone was entered at 535 feet. The water contains 
110 grains of solid matter per gallon. 

Florence. — Some of the oil wells in the vicinity of Florence encounter more or 
less water at various depths down to about 1,150 feet. The water is strongly 
mineralized and often is in large volume. A typical record is reported as follows: 

Record of well in sec. 23, T. 19 S., R. 69 W., near Florence, Colo. 

Feet. 

Surface materials s 0- 20 

Shale and sand}' shale ; flow of water ^ 260- 280 

Shale, with layers of limestone 280- 650 

Limestone 650- 695 

Sandstone 695- 699 

White sandstone, second flow 699- 722 

Shales, limestone, and sandstone ; very large flow 722-1 , 130 

Shales and sandstone _ 1 , 300-1 , 400 

Soft shale 1,400-1,600 

In 1905 an artesian well was completed 6 miles north of Florence, which is 
reported to have a flow of 360 gallons a minute from a 5 f -inch casing. It is located 
in the SW. i sec. 26, T. 18 S., R. 69 W., and has a depth of 1,230 feet. The water 
rises 6 feet above the surface and has sufficient head to rise 80 feet or more. The 
temperature of flow is 87°. Water was found at depths of 230 to 235, 300 to 345, 
and 815 to 900 feet, besides the main flow at 1,210 feet. The record is as follows: 

Record of well in SW. I sec. 2'6, T. 18 S. R. 69 W. 

Feet. 

Sandy loam, reddish 0- 13 

Conglomerate 13- 18 

Light-blue clay (Pierre) 18- 210 

Light-blue lime 210- 250 

Light-colored sand 250- 255 

Shale and limestone, alternating _ 255- 780 

Light-colored limestone 780- 810 

Light-colored sandstone 810- 825 

Shale, with hard layers, some limestone 825-1, 025 

Drab shale 1 , 025-1 , 195 

Sandstone, with hard laj^ers 1, 195-1, 210 

" Dakota " sandstone 1, 210-1, 230 

t 



62 ARKANSAS VALLEY IN EA8TEEN COLOEADO. 

Canyon. — Three miles east of Canyon there is a flowing well 900 feet deep which 
appears to derive its flow from a sandy member in the Pierre shale. Another well 
5 miles south, 360 feet deep, has a large flow from the same source, or the basal 
Laramie sandstone. A new well at the Sanitarium, 3 miles northeast of Canyon, 
has a depth of 1,670 feet. It is 6 inches in diameter and yields a 300-gallon flow 
under a pressure of about 30 pounds, probably from the "Dakota" sandstone. 

Portland. — This welUs 10 miles south of Portland, on a branch of Kitchie Creek, 
near the south margin of Fremont County. It flows about 600 gallons a minute 
from a 6-inch casing and has a depth of 1,135 feet. It begins in the upper beds of 
the Apishapa formation, at an altitude of about 5,550 feet, but no reliable record 
could be obtained of the beds penetrated. Probably the Niobrara group has a 
thickness of about 650 feet and the Benton about 415 feet, for it is stated that the 
" Dakota " sandstone was entered at a depth of 1,065 feet. The water contains some 
iron and other salts, but appears to be satisfactory for domestic use and irrigation. 
Two views of this well are given in PI. XXVII, which also show the deep hole washed 
out by the water that escapes along the side of the casing. This well indicates that 
wide areas of flat lands, extending east and north for many miles, are within reach 
of flowing waters which may prove to be valuable in reclaiming the land. Much of 
this area has the fertile, limy soils of the Apishapa formation. 

Chandler. — A short distance west of Chandler, which lies south of the city of 
Canyon, there is a flowing well 1,075 feet deep sunk in a syncline near the foot of 
the Wet Mountain Range. Its flow is derived from the "Dakota" sandstone and 
is reported to be 80 to 100 gallons a minute. The water is tepid, has a decided iron 
and sulphate taste, and deposits a yellowish-red precipitate on standing. Twd 
other wells in the same vicinity yield' flows from depths of 487 and 364 feet. 

St. Mary. — -A 1,670-foot well just east of St. Mary obtains a strong flow from 
Dakota sandstone. The water is " alkaline" and is not used. 

NONFLOWING DEEP WELLS. 

Ordway. — At Ordway, on the Missouri Pacific Railroad, several wells have been 
sunk which have not succeeded in obtaining a flow. The "Dakota" sandstone was 
penetrated by these and was found to contain an abundance of water, which, how- 
ever, would not rise higher than to 80 or 90 feet below the surface. The materials 
reported in one of the borings, which has a depth of 1,508 feet, are as follows: 

Record of horing at Ordway, Colo. 

Feet. 

Surface materials 0-42 

Black shale. 42-60 

Blue and gray shale 60- 90 

Shale and shells 90-116 

Blue shale 116-145 

Black shale 1 145-185 

Sandstone 185-245 

Black shale 245-270 

Gray shale 270-345 

Limestone, soft 345-410 

Gray shale, some limestone 410-473 



U. S. GEOLOGICAL SURVEY 



PROFESSIONAL PAPER NO. 52 PL. XXVII 








ARTESIAN WELL 10 MILES SOUTH OF PORTLAND, COLO. 
Depth about 1,000 feet; flow about 700 gallons a minute from Dakota sandstone. 



NON-FLOWING DEEP WELLS. 63 

Feet. 

Gray shale, darker below 473- 580 

Black shale 580- 650 

Gray shale 650- 700 

Shale with shells 700- 710 

Shale '..... 710- 765 

Brown shale 765- 785 

Light-gray shale 785- 800 

Brown shale 800- 825 

Shale and limestone layers 825- 845 

Black shale 845- 855 

Shale with limestone layers 855- 925 

Limestone and shale 925- 960 

Limestone 960-1, 010 

Black shale 1 , 010-1 , 325 

" Talc " 1, 325-1 , 327 

Black shale 1, 327-1, 410 

Sandstone (Dakota) containing some water 1, 410-1, 500 

This boring apparently began in the Pierre shale, passed through the basal 
limestone of the Timpas formation at 960 to 1,010 feet, but either did not penetrate 
sufficiently far into the "Dakota" sandstone to obtain flowing water or more likely 
the altitude of Ordway is too high to afford a flow. 

* Sugar City. — The boring at Sugar City reached a depth of 1,308 feet, but did 
not obtain a flow. This well is reported to have entered the "Dakota" sandstone 
at a depth of 1,230 feet. 

Arlington. — A well has been sunk in sec. 13, T. 21 S., R. 54 W., in the northeast 
corner of Otero County, 10 miles southwest of Arlington and 18 miles due east of 
Ordway. It has a depth of 715 feet, but, although it reached the "Dakota" sand- 
stone, the head was not sufficient to afford a flow, the water level coming only to 60 
feet of the surface. The supply appears to be ample, for the well was pumped 20 
gallons a minute. The following record is given: 

Record of well in sec. 13, T. 21 S., R. 54- W., 18 miles due east of Ordway, Otero County, Colo. 

Feet. 

Sand and clay 0-40 

Blue shale 40-180 

Sandstone : 180-187 

Gray shale 187-227 

Limestone 227-267 

Brown shale 267-372 

Limestone 372-377 

Sandy shale 377-432 

Slate 432-477 

Brown shale 477-584 

Slate 584-594 

Black sandy shale 594-688 

Gray sandstone 688-703 

Water-bearing sandstone 703-715 

Las Animas. — A well was sunk in 1903 in sec. 36, T. 21 S., R. 52 W., 6 miles 

- west of the Government well, to a depth of 720 feet. A satisfactory supply of water 

was found in sandstone at 452 to 474 feet, but, as it rose only to within 300 feet of 



64 ARKANSAS VALLEY IN EASTERN COLORADO. 

the surface the well is regarded as a failure. The following record was furnished 
by the owner, Mr. O. G. Scott: 

Record of well 8 miles north-northeast of Las Animas, Colo. 

Feet. 

Loam and sandstone 0-25 

Dark shale 25-452 

Dakota sandstone; water to —300 feet 452-475 

Dry sandstone 475-596 

Dark shale 596-656 

Gv&y shale with " bowlders " ( ?) 656-700 

"Talc" 700-710 

Gray shale lying on red shale: 710-720 

• This well began at the top of the Carlile formation and passed through the 
formations of the Benton group to the top of "Dakota" sandstone, at 452 feet. The 
sandstone is reported to be 144 feet thick and underlain by 124 feet of Morrison shales 
to the top of the "Ked Beds," at a depth of 720 feet. ' 

Oaddoa. — At this station, which is on the Atchison, Topeka and Santa Fe Rail- 
way, on the river bank, a well has been bored to a depth of 582 feet. The upper bed 
of the "Dakota" sandstone outcrops extensively in this vicinity, and the well reaches 
the lower part of the lower sandstone of the formation. It is 10 miles southeast of 
the Government well described on page 58. The water obtained at 285 feet was 
hard, so that the wells which are now in use obtain their supply from the upper bed 
at a depth of 70 feet, where the water is relatively soft. The following record is 
given : 

Record of well at Oaddoa, Colo. 

Feet. 

Surface materials •. 0-29 

Yellow clay 29-33 

Sandstone, soft water at 50 feet 33- 66 

Shale 66-175 

Sandstone, hard water 175-285 

Variegated shale, water to — 75 feet 285-300 

Sand rock, water to —60 feet 300-345 

Shale - 345-384 

White sand rock. 384-425 

Red shale and sand .' 425-492 

White slate 492-582 

Lamar. — At Lamar there are several wells 226 to 522 feet deep, which furnish 
water for the railroad and the town. Some of them afford a flow, but the head 
is very slight. The well at the railroad tank pumps 80 gallons a minute with the 
pump barrel 200 feet below the surface. Its record is reported as follows: 

Record of well at Lamar, Colo. 

Feet. 

Surface materials. 0-34 

Shale 34- 72 

"Talc vein" 72- 75 

Shale 75-198 

Dakota sandstone ; water to —20 feet 198-265 

Shale 265-270 



NON-FLOWING DEEP WELLS. 65 

. ' \ Feet. 

Sandstone; soft water 270-325 

Shale 325-400 

Sandstone 400-404 

Sandy shale 404r-460 

Sandstone; soft water, which at 480 feet rises to —60 feet and at 500 feet just flows 460-500 

Variegated shale — red, chocolate, and brown 500-527 

The variegated shales in the bottom of the well are probably at the top of 
the Morrison formation. At the waterworks in Lamar a large supply of water 
is pumped from the "Dakota" sandstone at a depth of 300 feet, rising to within 
28 feet of the surface. The water has the composition stated on page 80. 

A well 107 feet deep, in the NE. i sec. 36, T. 24 S., K. 47 W., found a large 
supply of water in "Dakota" sandstone. Its diameter is 5 inches and one large 
windmill does not pump it dry. The water is soft, but contains an appreciable 
amount of salts. 

Granada. — The railroad well at this place has the following record: 

Record of dee]) well at Granada, Colo. 

Feet. 

Surface materials; hard water 0-36 

Shale 36- 58 

Limestone yielding bad water 58- 60 

Shale : 60- 78 

Limestone 78- 80 

Gray shale : 80-195 

Black shale 195-323 

"Talc vein" 323-326 

Black shale 326-353 

Sandy shale ; some soft water 353-405 

Dakota sandstone; soft water 405-480 

Shale '. 480-^97 

White clay 497-504 

The original water level in the well was about 25 feet below the surface, but 
it is pumped down to below 80 feet, yielding about 80 gallons a minute. 

The town well at Granada, drilled in 1904, in the center of the town, has a 
depth of 480 feet, where a large supply of water is obtained. The water is soft 
and rises to within 30 feet of the surface. 

Amity. — The well at Amity has a depth of 384 feet, reaching the "Dakota" 
sandstone at 310 feet. The water rises to within 19 feet of the surface; the supply 
is very large, and the quality is highly satisfactory. The well is cased with 
100 feet of 7i-inch casing through sand and gravel to the first shale, 187 feet of 
6^-inch 6asing to shut out some very hard water at a depth of 187 feet, and 380 
feet of 5-inch casing reaching into the "Dakota" sandstone. In one report it is 
stated that the top of the "Dakota" sandstone is at 297 feet, consisting of 4 feet 
of sand lying on shale, and that the second sand with the principal flow was entered 
at 376 feet and penetrated 8 feet. The head of the water in this well is below the 
level of Arkansas River. 

Three miles north of Amity, in SE. J sec. 25, T. 22 S., R. 43 W., there is a deep 
well, sunk by the Sugar Beet and Irrigated Land Company in 1902. It is 699 

4551— No. 52—06 5 



66 ABKANSAS VALLEY IN EASTERN , COLORADO. 

feet deep, 8 to 6 inches in diameter, and yields a large supply of excellent soft 
water, which rises to within 100 feet of the surface. Some water was found at 
300 feet and other depths, but the water utilized is from the bottom of the well. 
The following record of this well was supplied by the company: 

Record of well 3 miles north of Amity, Colo. 

Feet. 

Gravel and sand 0-92 

Limestone 92-132 

Dark shale 132-610 

Dakota sandstone 610-699 

Holly. — At Holly there is a well which reaches the "Dakota" sandstone at 
296 feet and obtains a satisfactory supply of excellent water. At the sugar 
factory, one-half mile west of Holly, a new well 412 feet deep obtains a water 
supply which rises to within 20 feet of the surface. The diminished depth to the 
"Dakota" at this place indicates that the strata are rising, east ward from Granada, 
as shown in the section, PI. XXIII. 

Delhi. — ^At a siding on the Santa Fe Railway 8 miles north of Thatcher a well 
was sunk in 1901-2 by the railway company to a depth of 322 feet. The well 
draws water from several beds, from 132 feet down to its bottom. The original 
water level was 50 to 75 feet below the surface, but it has been greatly lowered 
by pumping. With the cylinder at 152 feet it yields 37 gallons a minute. The 
following record was furnished : 

Record of well at Delhi, Otero County, Colo. 

Feet. 

Clay ., 0- 75 

Dark-gray sand 75-110 

Light-gray sand 110-120 

Dark-gray sand, with water at 130 feet 120-141 

Light-gray sand 141-161 

Dark-gray sand 161-176 

Black shale.... 176-185 

Dark-gray sand 185-205 

Shale , 205-218 

White sand 218-305 

Water-bearing beds 305-322 

This boring begins near the bottom of the Graneros shale and penetrates 
nearly to the bottom of the " Dakota " sandstones. The failure of this well to afford 
a flow is due to outcrop of the sandstones in the depressions west and north. 

Tyrone. — This is a siding on the Santa Fe Railroad 8 miles south of Thatcher. 
The well was sunk in 1902 by the railroad company to a depth of 580 feet. It 
draws its main supply, which pumps 50 gallons a minute, from a depth of 577 
feet, with the pumping cylinder at 423 feet. The height to which the water rose 
originally is not stated. The following record is furnished: 

Record of well at Tyrone, Las Animas County, Colo. 

Feet. 

Loam and clay 0-30 

Limestone 30- 70 

Black shale with bad sulphur water at 175 feet, rising to —70 feet 70-345 

"Talcvem" 345-350 



NOlf-FLOWING DEEP WELLS. 67 

Feet. 

Black shale 350-438 

Sandstone (first " Dakota"), with water at 458 feet, which rose to about —375 feet 438-480 

Black shale 480-490 

Sandstone (second "Dakota"), main water supply 490-577 

Black shale ' 577-580 

This boring begins in the lower portion of the Timpas formation, passing out 
of the Timpas Hmestone at 70 feet and through 368 feet of beds of' the Benton 
group, with characteristic "talc vein" at 345 feet, to the "Dakota" formation 
at a depth of 438 feet. The low head of the water is due to the low level of "Dakota " 
sandstone outcrops to the west, north, and east. 

Trinidad. — Several deep borings have been made in and near Trinidad for 
gas, oil, and water, but only water has been obtained. One boring southwest 
of the city is claimed to have reached a depth of 3,000 feet. Two borings in the 
railroad yards have reached depths in excess of 2,600 feet and obtained water 
from the "Dakota" sandstone, which lies at a depth of 2,585 feet. One well, 
reported by the Colorado Southern Railroad Company, has a depth of 2,713 feet; 
at 2,595 feet an abundant supply of excellent water is obtained, which rises to 
within 195 feet of the surface. The well begins about 150 feet below the top of 
the Pierre shale. The following partial record is given: 

Record of railroad well at Trinidad, Colo. 

Feet. 

Loam and gravel 0- 42 

Gray shale, some water from 150 to 250 feet 42-2, 200 

Lime shale and black shale with some gas at 2,220 feet 2, 200-2, 400 

Black shale (Graneros) : 2,400-2,585 

" Dakota " sandstones, close and hard *. 2, 585-2, 713 

Barela. — A well sunk by the Colorado Southern Railroad Company at Barela 
has a depth of 1,340 feet, obtaining water which rises to within 300 feet of the 
surface, and pumps 30 gallons a minute. The following record has been furnished 
by the railroad company : 

Record of well at Barela, Las Animas County, Colo. 

Feet. 

Gravel and loam 0- 27 

Gray shale 27- 680 

Limestone (Timpas) 680- 704 

Black shale 704-1, 063 

First " Dakota" sandstone 1, 063-1, 213 

Shale 1,213- ? 

Second "Dakota" sandstone ? -1, 323 

Red rock 1, 323-1, 340 

This boring began in the Apishapa shales about 100 feet below the top of the 
formation and passed through the basal Timpas limestone at 704 feet. The Benton 
group has a thickness of '359 feet, in which the Greenhorn limestone was not reported. 
The "Dakota" sandstones have a thickness of 260 feet and the underlying "red 
rock" reported is probably in the Morrison formation. The thickness of shale 
between the upper and lower sandstones was not given. 

Watervale. — A well sunk by the Colorado Southern Railroad Company at 
Watervale, near the southeast corner of Las Animas County, has a depth of 327 



68 ARKANSAS VALLEY IN EASTERN COLORADO. 

feet. "Dakota" sandstone was found under gray shale at a depth of 100 feet 
and penetrated to 285 feet, where red rocks were entered and bored into for 42 feet. 
Water, which rose some distance, was obtained in the "Dakota" sandstone. 

Wetmore. — In Pueblo County, 1^ miles east of Wetmore, a boring for oil 
reached a depth between 1,300 and 1,400 feet. It penetrated the "Dakota" sand- 
stone for 30 feet. The rock was found to be very hard. Water was encountered, 
which rose to within 100 feet of the surface, which is a high mesa near the foot of 
the moiuitains. This boring is about a mile south of the flowing well described 
on page 62, but is on land about 450 feet higher. It began in terrace deposits 
capping Pierre shale. 

UNSUCCESSFUL DEEP BORINGS. 

Cheyenne Wells. — The well at this place was bored under the direction of the 
Department of Agriculture more than twenty years ago, by means of an appropria- 
tion provided by a special act of Congress. No official data have been obtained 
regarding its depth, record, and results, except the statement that it was unsuc- 
cessful. As considerable gas was encountered in its lower portion, a local company 
was organized to develop a gas supply by a second boring, which reached a depth 
of 1,700 feet and was then abandoned, as the gas was found to be of insufficient 
quantity. Through the kindness of Mr. McLane, of Cheyenne Wells, the following 
record was obtained: 

Record ofhoring at Cheyenne Wells, Colo. 

Feet. 

Clay: 0- 30 

" Magnesia " ; 1 - 30- 60 

Sandy gravelly clay - 60- 110 

White sandy clay 110- 130 

Soft white sand. ..'. 130- 145 

White sandy clay 145- 185 

Soft white sand 185- 215 

Soft black shale ; good water at 257 feet 215- 534 

White sandy shale ; gas 1 534-1 , 260 

Chalk rock; brackish water 1, 260-1, 330 

Fine sand 1,330-1,360' 

Soft black shale 1, 360-1, 460 

Soft white sand or limestone 1, 460-1, 510 

Black shale 1, 510-1, 700 

(Not given, but thought to be shale) , . 1, 700-1, 770 

In this boring a- large supply of excellent water was obtained at a depth of 
257 feet at the base of the Tertiary formations, but it did not rise far in the casing. 
The record appears to indicate that the Tertiary formations extend to 215 feet, 
but probably they really extend to 257 or 260 feet, where the black shale begins 
in the two shallow wells now in use at the railroad tank. The upper shales are 
undoubtedly Pierre, and the chalk rock at 1,260 to 1,330 is a portion of the Niobrara. 
The supposed limestone at 1,460 to 1,510 feet is probably the Timpas limestone, 
at the base of the Niobrara, and if this is the case the boring stopped in the top of 
the shales not far above the top of the "Dakota" sandstone. It was intended 
that the Government boring should be continued to 2,000 feet, but with the small- 
sized casing used in its lower portion the bit could not progress below about 1,770 



UNSUCCESSFUL DEEP BOEINGS. 69 

feet. It is unfortunate that the boring was not sunk to the depth intended, as 
there were excellent prospects of reaching the "Dakota" sandstone and obtaining 
water for a pump well. It would thus have thrown most important light on the 
head of the water and prospects in adjoining regions. 

Kit OarsQn. — ^A well bored at Kit Carson in 1870 by the Kansas Pacific Rail- 
road, which attained a depth stated by various authorities as 1,300, 1,460, and 
1,500 feet was also unsuccessful. Doubtless it penetrated practically the same 
beds as those below 300 feet in the Cheyenne Wells boring. 

STieridan Lake. — At Sheridan Lake a local company sunk a well to a depth of 
1,280 feet, and found considerable water, but without sufficient head to afford a 
surface flow. The boring is now abandoned. The lowest water in any appreciable 
volume was at a depth of 1,200 feet in a dark-colored sandstone, from which it rose 
to within 40 or 50 feet of the surface. No record is obtainable, but as the boring 
begins in the upper portion of the Niobrara chalk, doubtless the sandstone at 1,200 
feet is "Dakota." 

Hoehne. — At this station on the Santa Fe Railroad, 9 miles northeast of Trinidad, 
a boring was made to the depth of 936 feet, but, unfortunately, it was abandoned 
before it reached the "Dakota" sandstone, which should there be expected at a 
depth of about 1,100 feet. The boring was begun at the base of the Pierre shale, 
penetrated the Apishapa and Timpas formations, here about 700 feet thick, and 
passed low into the Carlile shale. Doubtless it would have found water in the 
"Dakota" sandstone, and, as the locality is nearly 300 feet lower than Trinidad, 
it might have obtained a flow. To the north of this place the depth to the ' ' Dakota " 
beds diminishes as the outcrop zone of the Niobrara formation is crossed, and the 
sandstone comes to the surface a short distance south of Thatcher. 

Thatcher. — In 1884 a boring was made at this place to a depth of 920 feet. 
It began near the top of the "Dakota" sandstone and penetrated several hundred 
feet into the "Red Beds." Some water was found near the bottom, which rose 
300 feet. No record was obtainable, and neither the quality nor the volume of 
water was stated. 

Troy. — At a transient settlement by this name, 25 miles north of Watervale, 
a boring 400 to 500 feet deep was sunk several years ago. It began in "Dakota" 
sandstone. No record or other information was obtained, except that it was 
regarded a failure. 

Rouse Junction. — ^At Rouse Junction, a station on the Denver and Rio Grande 
Railroad southeast of Walsenburg, the railroad company made a boring to a depth 
of 2,058 feet, but did not find an adequate water supply. A small amount of 
fresh water appeared at 700 and 1,760 feet, and of salt water at 890 feet. These 
waters rose for some distance, but the greatest height was more than 200 feet 
below the surface. The following record was furnished by the railroad company: 

Recordof well at Bouse Junction, Colo. 

Feet. 

Shale 20-800 

Coarse white sandstone 800 

Black shale; bad water 850 

Hard white sandstone 870 

Hard rock (reported as granite) 930 



70 ARKANSAS VALLEY IN EASTERN COLORADO. 

Feet. 

Hard white sandstone 940 

Black shales 950 

Hard white sandstone 960 

Slate 1,010 

Shale • 1,020 

Hard white sandstone and quicksand 1, 030 

Hard white sandstone and quicksand 1, 140 

Coarse white sand with a little water 1, 150 

Coarse red sandstone 1, 160 

Coarse green sandstone 1, 190 

Pink slate and sand and " granite " 1, 210 

Red sand 1,290 

Pink slate 1,320 

Drab sand with shells 1, 350 

Fine hard white sand 1, 380 

Fine drab sand and white hard clay 1, 390 

Red flinty rock .• 1, 450 

Fine gray sand, very hard 1, 500 

Red sand 1, 540 

Hard white sand 1, 960 

Red fine hard sand. _ 2, 058 

This boring was begun near the base of the Pierre shale, and the shales reported 
to a depth of 800 feet are mainly Niobrara and possibly the upper shale of the Ben- 
ton. The "Dakota" sandstone appears to have been reached at 1,140 feet and 
to have continued to not far below 1,500 feet. The lower 300 feet or more were 
in the "Red Beds" and it was from them that the fresh water at 1,760 feet was 
obtained. The salt water at 890 feet was in sandstone of the Benton group. 
Apparently the "Dakota" sandstone yielded no water, a most discouraging indi- 
cation, for its capabilities seem to have been thoroughly tested. The explanation 
probably is that, owing to the extensive outcrops of the "Dakota" formation, a 
short distance north and east, no head is possessed by whatever water may be 
passing through the sandstone. There is also a likelihood that the many dikes 
which penetrate the formations near Rouse Junction, particularly to the west, 
may cut off the underground flow. 

Walsenburg. — At Walsenburg an unsuccessful boring was made sometime 
ago for gas. It was 1,300 feet deep and entirely in the Pierre shale, which here 
has a thickness of about 1,700 feet. 

Ouchara. — On Cuchara River 7 miles below Walsenburg an 800-foot boring 
was made for coal, oil, or gas. It found an abundant supply of sulphur water, 
which is pumped to the surface. The boring probably reached the top of the 
"Dakota" sandstone. 

Elmoro. — A 400-foot boring at Elmoro is entirely in Pierre shale and yielded 
no water. 

Salt Creek. — ^This place is a siding on the Denver and Rio Grande Railroad at 
the crossing of Salado Creek, 6 miles south of Rouse Junction. The railroad com- 
pany made a test boring to a depth of 2,030 feet, which did not find a sufficient 
supply of good water. Analyses of the two principal waters are given on pp. 80-81. 
The following materials were reported, but the record evidently is unreliable : 



UNSUCCESSFUL DEEP BOEINGS. 71 

t 

Partial record of deep horing at Salt Creek siding, Las Animas County, Colo. 

Feet. 

Gravel 0- 6 

Hard limestone; water at 70 feet rose to — 3 feet 6- 71 

Black shale ; thin limestone layers 71- 250 

Sand and shales; water at 283 feet rose to — 140 feet 250- 285 

Black and white sand 285- 335 

Gray sand 335- 352 

Dark sand 352- 365 

Light-gray sand. 365- 380 

Red sand and hard clay 380- 410 

White shale; water at 440 feet rose to —220 feet 410- 450 

Gray hard sandstone 450- 495 

Greenish sand and sandstone 495- 630 

Gray sand 630- 750 

Dark-gray sand; water at 840 feet rose to — 540 feet 750- 845 

White sand 845- 855 

Dark-gray sand 855- 870 

Red sand; water at 1,005 feet rose to — ^705 feet 870-1 015 

Red sand and " granite " 1, 025 

At 1,545 feet water rose to —900 feet, and at 1,800 feet rose to —600 feet. 

This boring began in the lower portion of the Pierre shale, penetrated the Nio- 
brara from about 300 to about 950 feet, and the Benton from about 950 to about 
1,350 feet, where the "Dakota" sandstone was entered. It is the latter formation 
which yields the water at 1,545 feet, a water too highly mineralized to be of any 
use. The lower 200 feet of the well were probably in "Red Beds." The failure of 
this well to yield a satisfactory water supply is in line with a similar experience 
at Rouse Junction, in the adjoining county to the north. The amount of water at 
Salt Creek was not ascertained, but it was believed not to be great. This and the 
experience of the Rouse Junction well indicate either that the water leaks out to 
the northwest, or that its circulation is impeded by the many dikes of igneous 
rock which intersect the formations in the surrounding region. This diminished 
circulation is also indicated by the salinity of the water, which we should expect 
would be greatly decreased if there were a free underground passage to the 
canyons north and east; moreover, in these canyons very little water is seen to 
come out of the formation. 

Boone. — In 1903 a deep boring was made at Boone to explore for oil or gas. It 
reached the top of the "Dakota" sandstone, which was not penetrated sufficiently 
to afford a water supply. The following record is furnished : 

Record of horing at Boone, Colo. 

Feet. 

Surface materials 0- 25 

Shale 25-1,560 

Limestone 1, 560-1, 610 

Shale 1,610-1.720 

Limestone 1, 720-1, 740 

Shale with " talc vein " 1, 740-2, 200 

" Dakota " sandstone 2, 200- 

The first 1,000 feet of shale probably are of the Pierre, while the Niobrara, 
with its Apishapa shales above and Timpas limestone below, extends to 1,740 feet, a 



72 AEKANSAS VALLEY IN EASTEEN COLORADO. 

thickness of about 740 feet. The CarUle, Greenhorn, and Graneros beds comprise 
a thickness of 460 feet. This boring is near the axis of a deep north-pitching syn- 
cHne — a fact which accounts for the great thickness of Pierre shale. 

Puehlo. — In 1903 two deep borings were sunk in north-central Pueblo County, 
with the hope of finding oil or gas, but without success. Both borings are situated 
north of Arkansas River — one 1,900 feet deep, 7 miles northeast of Pueblo, and 
the other 2,655 feet deep, 10 miles northeast of Pueblo. The shallower boring 
appears not to have reached the "Dakota" sandstone, but found some water 
which rose to within 550 feet of the surface. The 2,655-foot well penetrated the 
"Dakota" sandstone 55 feet and found water which rose 1,000 feet or more. The 
following records were furnished: 

Records of wells 7 and 10 miles northeast of Puehlo, Colo. 

Well No. 1: Feet. 

Shale 0-1,400 

Limestone > 1, 400 

Sandstone 1, 440 

Shale (?) 1,875 

Sandstone (probably Carlile) 1, 875-1, 900 

Well No. 2: 

Shale 0-2,000 

• Limestone 2,000-2,100 

Sandstone (Carlile) 2,100-2,140 

Shale , 2, 140-2, 600 

" Dakota " sandstone 2, 600-2, 655 

The altitude of the first well is about 4,900 feet and its precise location is 4^ 
miles north and a half mile west of Baxter siding, on the Missouri Pacific Railroad. 
The other boring is at an altitude of 4,750 feet and its approximate location is 6 
miles north and 3 miles west of Nyburg siding, on the Missouri Pacific Railroad. It 
is probable that if the "Dakota" sandstone had been more deeply penetrated by 
this boring the water would have risen to within 100 feet of the surface, but the boring 
is situated on land too high for artesian flow. 

Colorado City-. — Deep borings at Colorado City penetrated the steeply dipping 
beds of the foothills, but did not prove successful. Two deep wells were bored 
there by a local oil company in 1894 and 1895. Boring No. 1 was located on the 
NW. i of NE. 1 sec. 2, T. 14 S., R. 67 W. It reached a depth of 2,020 feet, where 
operations were stopped by the collapse of a string of casing. Below the first 30 
feet of surficial materials the formation penetrated was black shale, except at 
1,247 feet, where a 5-foot bed as hard as granite was reported, which yielded some 
gas. 'The bormg was entirely in Pierre shale. Boring No. 2 was located on the 
SW. i of NE. i sec 2, T. 14 S., R. 67- W., and had a depth of 1,300 feet, entirely in 
shale below the first 60 feet. Both holes are now full of water. 

CaThan. — A boring at Calhan, doubtless entirely in the Laramie formation, was 
sunk to a depth of 566 feet, and obtained a small amount of water at 90 feet. Coal- 
bearing beds were reported at 250 feet and lower, but the beds were thin and the 
coal was of poor quality. The following record was reported by the Chicago, Rock 
Island and Pacific Railroad Company: 



SOURCE OF AETESIAN WATER. 73 

Record of boring at Calhan, Colo. 

Feet. 

Sand - 0-23 

Sandstone 23 - 38 

Dark sandy shale 38 - 63 

Clay and sandy shale grading into soft sandstone 63 -142 

"Soapstone;" thin coal layer at 232 feet 142 -255 

Shale 255 -306 

Sandy limestone 306 -314 

Sandy shale with coaly layers 314 -323 

"False coal" 323 -324 

Fireclay 324 -325J 

Dark shale 325|-329 

Sandy shale 329 -336J 

"False coal" , 336J-337 

Micaceous sandy shale; ^-inch coal layer at 360 feet 337 -361 

''Soapstone" , 361 -416 

Micaceous sandy shale 416 -432 

"False coal and poor coal" 432 -435 

Shale 435 -480J 

Sandy false coal , 480J-484^ 

Poor coal .'. 484J-487 

Micaceous sandy layer with some shale 487 -546 

Sandy false coal 546 -551 

Shale 551 -556^ 

Shale and sandy shale 556J-566| 

Franceville Junction. — ^At this place, which is on the slope southeast of Colo- 
rado Springs, a 1,250-foot boring is reported, which was entirely in Pierre shale and 
yielded neither water, oil, nor gas. 

Monument. — A 765-foot boring is reported at Monument. It began in or 
above the Laramie beds and probably penetrated Pierre shale, but without result. 

Florence. — In the oil fields about this place there are many deep borings, mostly 
in the Pierre shale, which rarely find much water. One with a depth of 3,021 feet 
was entirely in shale, except 10 feet of dark hard rock at 2,680 feet. It encountered 
no water. 

SOURCE OF THE " DAKOTA " WATER. 

The artesian waters of the "Dakota" sandstone enter this formation in the 
outcrop zone along the foot of the Rocky Mountains and also in the wide area of 
exposures in the southeast corner of the State. The exposed surface of the sand- 
stone directly absorbs a portion of the rainfall and some of the water of streams 
crossing the outcrop also sinks into the porous beds. In the southeast corner of 
the State the formation is extensively overlain by deposits of gravel and sand, and 
much of the water which falls on this surface passes underground and in part enters 
the "Dakota" sandstone. Some of the water absorbed on the higher ridges escapes 
again at lower levels along the canyons and draws, either in springs or as small 
seeps. These are occasionally observed along the hillsides, and doubtless there 
are many others covered by talus and wash. 

The area of "Dakota" sandstone exposed in the "hogbacks" along the foot 
of the mountains is relatively small; the outcropping beds usually dip steeply, 



74 ARKANSAS VALLEY IN EASTERN COLORADO. 

and much of the rock is so hard that water falhng upon its surface runs off into 
the adjoining shale valleys, so that probably only a limited amount passes under- 
ground in this zone. Probably most of the water is absorbed in the wide outcrop 
area extending from Huerfano Eiver to Apishapa River, northwest of Thatcher, 
and especially in the wide plateaus south and southeast of La Junta. In the latter 
area the sandstone constitutes the surface for many square miles; much of the 
land is level or gently sloping and the sandstone is soft, so that it is capable of 
absorbing a large volume of water. On the other hand, this region is traversed 
by numerous deep canyons cut entirely through the "Dakota" sandstone, so that 
part of the underground drainage of the formation is intercepted. Purgatory 
River and Smith and Muddy creeks probably intercept all of the underground 
drainage of the sandstone in the region north and northwest of the Mesa de Maya. 

DEPTHS TO "Dakota" sandstone. 

Owing to the irregular dips of the rocks in southeastern Colorado, the depth 
to the water-bearing "Dakota" sandstone varies considerably in different portions 
of the district. From a study of the distribution of the overlying formations and 
a knowledge of their thickness, obtained by measurements on the surface and in 
wells, the position of the top of the "Dakota" sandstone has been ascertained as 
shown on the map, PL XXV. This map also shows the area in which the "Dakota" 
sandstone is at or near the surface and the region in which there is no "Dakota" 
sandstone. It will be sfeen from this illustration that, along the greater part of 
the Arkansas Valley, the water-bearing horizon lies at a moderate distance below 
the surface and over wide areas it is within the reach of wells 300 to 1,500 feet 
deep. In a wide district extending from northeast of Pueblo to northwest of 
Ordway the strata dip steeply into a deep basin, so that in northeastern Pueblo 
County, northwestern Otero County, central and eastern El Paso County, and 
Lincoln County the "Dakota" sandstone lies too deep for well drilling, and, more- 
over, the land in this region is too high for the water to flow. The beds also lie in 
a deep basin in central and southern Huerfano and Las Animas counties, as well 
as in the area about Florence. From Portland to Pueblo, in the vicinity of Arkansas 
River, the "Dakota" sandstone is less than 1,200 feet below the surface, and in a 
small anticline 6 miles west of Pueblo the top of the formation is exposed in the 
river bed. East of this exposure the dips increase gradually, so that the depths 
are about 1,200 feet at Pueblo, 1,900 feet at Nyburg, and about 2,000 feet at Boone, 
which is near the center of the basin. East of Boone the amounts diminish gradu- 
ally, being 1,800 feet at Nepesta, 1,270 feet at Fowler, 1,033 feet at Manzanola, 
690 feet at Rocky Ford, and 340 feet at La Junta. There is still further decrease 
to Las Animas, a short distance east of which the "Dakota" sandstone reaches 
the surface, outcropping along the bottom of the valley nearly to the mouth of 
Big Sandy Creek. East of this point the dip carries the beds down again and the 
depths gradually increase to 405 feet at Granada, which is in the center of a shallow 
basin. On the east slope of this basin there is a gradual rise to a depth of 200 feet 
at Coolidge. Many of these features are shown on Pis. XXIII, XXV, and XXVI. 



AREA OF ARTESIAN FLOW. " 75 

The figures above given are to the surface of the "Dakota" sandstone, and, 
while in many districts a flow of water is obtainable from the top bed of this forma- 
tion, the principal supply is usually looked for in lower beds, 100 to 160 feet deeper. 
In Kiowa County a prominent anticline extends northward from the Arkansas 
Valley, raising the beds in a low arch which extends northward to Kit Carson 
County. Owing to this uplift the "Dakota" sandstone lies at moderate depths 
as far north as the Union Pacific Railroad, especially in the lowlands of Big Sandy 
and Big Spring creeks. Unfortunately, however, all of this region is too high for 
artesian flows. Along the Rocky Mountain front the "Dakota" sandstone varies 
greatly in attitude, and in the vicinity of Colorado Springs and for several miles 
north and south the dips are steep and the sandstones are carried rapidly beneath 
the surface, soon reaching a depth of 3,000 feet. In the region northwest of Pueblo 
where the dips are gentler, the depths are much more moderate and the sandstone 
may be reached by wells 200 to 1,000 feet deep over an area of considerable extent. 
Along the base of the Wet Mountain Range the "Dakota" sandstone is extensively 
exposed, except to the south near Huerfano River, where it dips steeply under the 
great basin in which the Spanish Peaks are situated. On the east side of this 
basin there is a zone passing through Huerfano, Cuchara, Hoehne, Elmoro, Barela, 
Trinchera, and Watervale, in which there is a gradual increase of depth from east 
to west of 600 to 1,500 feet in greater part. 

AREA OF FLOW. 

Apparently the "Dakota" sandstone contains water throughout its extent, 
especially where it passes underground below the younger formations. As explained 
above, the sandstone receives much of the water at moderately high elevation, so 
that this water possesses considerable head in its passage underground. This 
head is sufficient to afford flows in nearly all of the lower lands near Arkansas 
River and along some of the confluent valleys, especially to the west. The areas 
in which flows may be expected are shown by the overprinted patterft on the map, 
PI. XXV. This representation is based on the observed pressures in wells, together 
with deductions as to gradient slopes drawn between many points along the out- 
crops of the water-bearing beds. These lines of the grade of the water head have 
been found to slope from the outcrops at high levels, where the water passes under- 
ground, to the outcrops at lower levels where there is leakage from springs. The 
principal area of low-level leakage in the district is along Arkansas River, between 
Las Animas and the mouth of Big Sandy Creek, where the "Dakota" sandstone 
is free to lose ranch of its water, consequently the head of the water becomes zero 
along this outcrop zone. The hydrostatic gradient rises to the southwest, but not 
rapidly, owing to the low declivity of the Purgatory Valley, which cuts into and 
through the sandstone for many miles. West of longitude 104° the rate of increase 
is very much higher, although it is locally diminished by the deep valleys of Apishapa 
and Huerfano rivers. Although the sandstones lie high on the mountain slopes 
in the western portion of Pueblo and the eastern portion of Fremont counties, 
there is a rapid diminution of head toward Pueblo, possibly due in part to the rise 
of the formation to the surface along the river 6 miles west of Pueblo. 



76 * ARKANSAS VALLEY IN EASTEEN COLORADO. 

The flowing wells south of Portland, at Pueblo, Fowler, Manzanola, Kocky 
Ford, Holbrook, La Junta, and Amity are along the main zone of flow. At La Junta 
there was originally a flow of considerable pressure, and also at Lamar, but pumping 
has reduced the water level considerably below -the present surface of the land. 
Flows at Timpas and Thatcher show an extension of the flow area to the southwest 
up the Timpas Valley, and similar lateral extension may be expected in the Apishapa, 
Huerfano, St. Charles, and other large valleys leading into Arkansas River. At 
Ordway and Sugar City the water-bearing beds appear to have been reached, but 
the land was too high for a flow and this probably was also the case at Sheridan 
Lake and Eat Carson in the wells sunk and abandoned long ago. The Government 
well northeast of Fort Lyon evidently was near the northern margin of the flow 
area, as its pressure was very slight, and two wells to the north and northwest 
have water levels considerably below the surface. The well 10 miles due south of 
Portland indicates a wide extension of the flow area in the southeast corner of 
■Fremont County and adjacent portions of Pueblo County. A small flowing well 
on Plum Creek 20 miles south of Granada indicates that flows may be expected in 
the lower valleys in the central-eastern portion of Prowers County, probably as 
far south as'South Butte Creek. The water level 100 feet below the surface at 
Trinidad and 80 fee;t below the surface at Barela indicates that the area of flow does 
not extend as far up Purgatory River and its branch valley as originally supposed. 

PRESSURE OR HEAD OF THE WATERS. 

As explained above, the waters in the "Dakota" sandstone under the greater 
part of southeastern Colorado possess considerable pressure, which ordinarily is 
sufficient to bring the water to the surface and in portions of the district to carry 
it to a greater or less distance above. In Pueblo the wells have a pressure of 50 
pounds to the square inch, and at Manzanola it is reported that the original pres- 
sure was 55 pounds. At Rocky Ford and Holbrook the water was found to have 
sufficient pressure to rise 80 feet, or more, in the pipe. At La Junta the well south 
of the town is about 150 feet higher than the depot, and when the well was first 
sunk the water had sufiicient force to rise considerably above the surface. A heavy 
draft on the water supply at La Junta has since lowered the water level so greatly 
that even the wells on the lower land do not flow. In PI. XXVIII the head of the 
waters is shown, and in the following table are given data from various flowing and 
nonflowing wells, throwing light on the head of waters in the "Dakota" sandstone. 
Unfortunately, it was impracticable to obtain the pressures, or facts relating to the 
water level, in some of the wells, and even the figures given in most cases are only 
approximate. 




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QUANTITY OF WATER. 

List of wells in eastern Colorado affording data as to Tiead of waters. 



77 



Locality. 



Height to 




which wa- 


Altitude of 


ter will 


the land. 


nse. 




Feet. 


Feet. 


100± 


5,550 


+ 80 


5,400 


138 


4,750 


138 


4,670 


115 


4,690 


80 


4,177 


?126i 


4,251 


+150 


4,061 


+ 80 


4,260 


+ 27 


4,480 


+ 50 


4,691 


10 


3,955 


46 


3,900 


- 80 


4,300 


- 60 


4,180 


-300 


4,100 


- 15± 


3,765 


'0 


3,592 


- 25 


3,445 


- 19 


3,450 


-100 


3,550 


- 50 


5,057 


-195 


5,980 


-300 


5,723 


-100 


6,000 


- 50 


4,065 


-200 


6,128 


-900 


• 6,480 



Head of 

water 

above sea 

level. 



FLOWING WELLS. 

Portland (10 miles south) 

Florence (6 miles north) 

Pueblo (South) 

Parriss House 

Grand Hotel 

Rocky Ford 

Manzanola ." 

La Junta (originally) 

Holbrook 

Timpas 

Bloom 

Fort Lyon 

Blackwell ranch (Plum Creek) 

NONFLOWING WELLS (WATER BELOW SURFACE) 

Ordway 

Arlington. (10 miles southwest) 

Las Animas (10 miles north) i 

Caddoa 

Lamar 

Granada 

Amity 

Amity (3 miles north) ^ 

Delhi 

Trinidad 

Barela 

Wetmore (IJ miles east) 

Sheridan Lake 

Rouse Junction 

Salt Creek ♦ 



Feel. 

5,650± 
+5,480 

4,888 ■ 

4,810 

4,805 
+ 4,257 
? 4, 377 
+ 4,210 

4,340 
+4,507 
+4,741 

3,965 

3,946 

4,220 

4,120 

3,800 

3,750± 

3,592 

3,420 

3,431 

3,450 

5,007 

5,785 

5,423 

5,900 

4,015 

5,928 

5,580 



The lines in PI. XXVIII are constructed from the altitudes of "Dakota" sand- 
stone outcrops and the water levels given in the above t.able. It is assumed that the 
gradients of head are uniform from point to point, as shown in the diagram, fig. 2, 
and this is found to be verified at numerous points in the Arkansas Valley. ■ 



QUANTITY OF 



" DAKOTA" 



WATERS. 



The volume of water available from the "Dakota" sandstone in eastern Colo- 
rado is variable, and in portions of the region it has been found inadequate. The 
three principal factors in this connection are the original volume of supply, the head 
of the water, and the porosity of the sandstone. No matter how much water is 
available along the intake zone, nor the head that may be developed in its passage 
to lower levels, there can be but little volume of water available if the sandstone 
is not porous. In its surface outcrops, as well as in the borings, the rock is found 
to vary considerably in porosity, but in general it usually appears to be capable 
of holding a moderately large volume of water. The amount of water that passes 
underground seems to be large, judging from the wide area of the formation exposed 
and its surface porosity, but much of the water taken in at high altitudes is free to 



78 ARKANSAS VALLEY IN EASTERN COLORADO. 

escape at lower ones, so that from this cause there is not only loss of water but 
diminution of head. Where the rock is saturated with water and the head is high, 
a well tapping the sandstone will yield a larger flow than one in an area where the 
pressure is low. As heretofore explained, nearly all the pressures in the Arkansas 
Valley are low, so that there is relatively little power to force the water into the 
sandstone interstices in the vicinity of the well, so as to sustain a vigorous flow. In ' 
most of the wells in the Arkansas Yalle}^ only a moderate volume of water was found, 
"and, when the wells are subjected to pumping, the water surface is quickly lowered 
in most cases. 

The wells at Rocky Ford exhibit a larger volume of water than any others in the 
Arkansas Valley below Pueblo. Of the several that have been bored, the larger 
ones have sustained a flow of 100 to 115 gallons a minute. The well at Manzanola, 
only 10 miles west, yields less than 40 gallons a minute, and the well at Fowler only 
half a gallon a minute. This rapid diminution to the west apparently is- due to 
diminished porosity of the sandstone. There is similar but less marked diminution 
to the east, as illustrated at La Junta. At this place there are several wells which 
originally flowed 12 to 35 gallons a minute, but vigorous pumping has lowered the 
head greatly and materially diminished the volume. North and northwest of La 
Junta the volume increases, a flow of 100 gallons a minute being reported at Hol- 
brook. About Las Animas the wells have flows of 10 to 20 gallons. At Caddoa, 
Lamar, Granada, and Amity, where the waters are pumped, supplies of 40 to 80 
gallons a minute are obtained. In the various wells along the Santa Fe Railroad 
southwest of La Junta the amount of water flowing or available for pumping varies 
greatly. At Delhi 37 gallons and at Tyrone 50 gallons are obtained. At Timpas 
and Thatcher the volume was very small, but at Ayer the poor water obtained 
had a flow of 25 gallons. In the vicinity of Pueblo the volume also is variable. 
The first well in South Pueblo flows 100 gallons a minute, of mineral water, while 
other wells in the vicinity flow 13 to 25 gallons. 

The well having the largest flow in the Arkansas Valley is the one 10 miles south 
of Portland, where, from a depth of about 1,100 feet, about 600 gallons a minute 
flow from a 6-inch casing. .It is possible that the large amoimt of water in this 
locality is due to the proximity to the intake zone along the mountain front a short 
distance south and west. It gives promise that in the extensive prairies lying 
east and north, similar large flows may be obtained, which could be used extensively 
for irrigation. 

In the eastern portion of Huerfano and the western portion of Las Animas coiin- 
ties there appears to be but a limited supply of water in the "Da^kota" sandstone, 
except about Trinidad and southeastward, where some of the wells obtain fair sup- 
plies by pumping. Deep borings at Rouse Junction and Salt Creek, on the Denver and 
Rio Grande Railroad, found only a very small amount of water in the "Dakota" 
sandstone, and at the latter place it was too much mineralized for use. Probably 
the small volume of water in this district is due to the escape of the underground sup- 
plies in the outcrops of "Dakota" sandstone at lower levels to the east. Possibly 
also the flow of underground currents is greatly impeded by the numerous igneous 
masses which traverse the strata in manv directions. 



ANALYSES OF WATERS. 79 



QUALITY OF THE " DAKOTA" WATERS. 



All waters which flow over or through rocks and soil dissolve various chem- 
ical compounds, the nature and amount of which have great local variation. Water 
passing through pure sand or sandstone can be contaminated only to a very slight 
degree, but nearly all rocks contain soluble minerals, especially shales, limestones, 
and red beds, which often yield a large amount of salts to waters which come in 
contact with them. Red beds generally contain gypsum and salts of various kinds 
and yield highly mineralized waters. The deep waters of the Arkansas Valley 
vary greatly in quality, but nearly all contain a noticeable amount of mineral mat- 
ter. Only a few analyses are available, and these are given in the following tables. 
The chemicals are reported in their theoretic combinations, and it should be pointed 
out in this connection that there is considerable difference of opinion among chem- 
ists as to the probable compounds indicated by analyses. Most of the waters from 
the "Dakota" sandstone in the Arkansas Valley region contain 50 to 100 grains 
per gallon of minerals. Sulphate of soda, or Glauber's salts, is the most prominent 
constituent, usually with smaller amounts of sodium chloride, or common salt, and 
sodium carbonate. Small amounts of carbonates of lime and magnesia appear in 
all the analyses reported, and usually there is also some sulphate of lime or gypsum. 

In some districts the quality is satisfactory; in others the waters are much 
mineralized. In the vicinity of Pueblo the principal flow contains so large an 
amount of saline ingredients that it is regarded as a valuable medicinal agent and 
is extensively bottled as such. At Grand Hotel the flow, at 1 ,050 feet near the top 
of the "Dakota" sandstone is reported to be of excellent quality. At Fowler, Man- 
'zanola, Rocky Ford, La Junta, Las Animas, Caddoa, Lamar, and Granada the 
quality is very satisfactory. At Ayer. and Thatcher the water contains too much 
mineral for use in locomotives, while at Trinidad and Barela it is satisfactory for this 
use. In the well 10 miles south of Portland the water contains considerable iron, 
but appears to be satisfactory for drinking and irrigation. At Salt Creek and Rouse 
Junction waters of decidedly saline character were reported. At St. Mary the 
water is too alkaline for use. 



80 



AKKANSAS VALLEY IN EASTEKN COLOKADO. 



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81 



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4551— No. 52—06- 



82 AEKANSAS VALLEY IN EASTERN COLORADO. 

In the analysis of the water of the first well at La Junta it is reported that when 
the analysis was made the water had deposited a slight brown sediment containing 
iron, manganese, silica, and a trace of phosphoric acid, all of which, except the last, 
are included in the analysis. Free and semicombined carbonic acid (COj), 124.4 
parts per milion ; total COj, 250.2 parts per million. A trace of lithium was found. 

When the water from the first artesian well at Rocky Ford was received in 
Washington it had deposited a sediment containing silica, iron oxide, a trace ( ?) of 
alumina, and phosphoric oxide. Traces of bromides (?), iodides, and phosphates 
were found in the water and some organic matter not determined. Boron, fluorine, 
and barium were absent. Free and semicombined carbonic acid (COg), 106.57 parts 
per million; total COj, 176.90 parts per million. 

WATERS OF THE "RED BEDS" AND THE MORRISON FORMATION. 

Under the greater part of southeastern Colorado the top of the "Red Beds" lies 
100 to 300 feet below the base of the "Dakota" sandstone. In the region north of 
Arkansas River and east of Fountain Creek these "Red Beds" are too deep 
to be reached by ordinary well drilling, but along the river valley and south- 
ward they are at moderate depths. The deep borings at La Junta, Manzanola, 
Thatcher, Rouse Junction, Salt Creek, Caddoa, Fort Lyon, and Bloom penetrated 
more or less deeply into the "Red Beds," but obtained no satisfactory water supplies. 
At a few points in Kansas the "Red Beds" have been found to contain good 
water, but in most cases it is too highly mineralized to be of any use. Probably 
water-bearing strata will be found in the "Red Beds" in Colorado, but it is doubtful 
if any of them will yield useful supplies, and ordinarily a boring should be discontinued 
as soon as it enters the "Red Beds." The Morrison formation includes thin beds of 
sandstone which often contain water, but the amount so far found is too small to be of 
value. At Manzanola the " Red Beds " were penetrated from 1,653 to 2,110 feet and 
several water-bearing strata were found, but it is reported that the water was very 
impure. In the Bloom boring, the "Red Beds" extend from 455 to 1,162 feet and 
yielded some water of bad quality at 1,006 and 1,145 feet, of which analyses are given 
in the table below. At Rouse Junction the water found in the "Red Beds" at a 
depth of 1,760 feet was reported as "fresh," but it rose only about 200 feet. The 
following are analyses, made by W. A. Powers, for the Atchison, Topeka and Santa 
Fe Railway Company, of waters from the "Red Beds" at Bloom and from the 
Morrison formation at La Jimta and Caddoa, at the depths stated : 



ANALYSES OF WATERS. 

Analyses of tvaters from "Red Beds " and Morrison formation in eastern Colorado. 

[Parts per million.] 



83 





Bloom. 


La Junta. 


Caddoa. 


Constituent. 


1,006 leet. 


1,145 feet. 


663 feet. 


757 feet. 


440 feet. 


560 feet. . 


Sodium, Na 


2,131 


846 


323 


270 


586 


753 


Pnt.R.Rsinni, "K" 






146 

88 

1,844 

221 
1,871 


229 

65 

1,342 

254 

553 


23 

24 
572 

24 
136 

56 


12 
6.4 
424 

11 
109 

17 


143 

75 

1,282 

39 

329 


38 


Magnesium, Mer 


23 


Sulphuric acid, SO^ 


702 


Chlorine, CI 


82 


Carbonic acid, CO3 


587 


Silica, SiOs. . . . 




Iron oxide+ aluminum oxide, Fe303+Al20a 










Organic and volatile 


255 


138 


66 


58 


199 


136 


Other constituents 


















Total solids 


6,556 


3,427 


1,224 


907.4 


2,653 


2,321 







Analyses of waters from " Red Beds " and Momson formation in eastern Colorado. 
[Expressed in hypothetical combinations and in grains per gallon.] 





Bloom. 


La Junta. 


Caddoa. 


Constituent. 


1,006 feet. 


1,145 feet. 


663 feet. 


757 feet. 


440 leet. 


560 feet. 


Sodium sulphate 


159.63 

21.29 

148.36 


116.13 

24.56 

4.92 


49.54 
2.31 
4.40 


36.70 
1.40 
7.70 


101. 18 
3.73 


60.79 


Sodium chloride 


7.96 


Sodium carbonate 


48.72 


Calcium sulphate 


9.38 
13.94 




Cfllcinm oai'bonn.tp 


21.30 


33.61 


3.32 


1.80 


5.62 


Mflgnftsinm snlphfl.te 






17.85 


13.20 


4.90 
3.26 


1.30 
1.00 


15.31 


4.77 






Iron and alumina 










Organic and volatile matters 


14.93 


8.08 


3.85 


3.40 


11.60 


7.93 






Total solids 


383.36 


200.50 


71.58 


53.30 


155. 20 


135. 79 







WATERS OF LARAMIE AND ASSOCIATED FORMATIONS. 

The Fox Hills (Trinidad), Laramie, and overlying formations all contain water, 
but unfortunately these formations are so distributed that their water supplies are 
not likely to be very useful. The area extending from the Raton Mesa to the Spanish 
Peaks and beyond is a rough upland of high ridges and steep-sided valleys, and, 
moreover, the conditions are not favorable for flowing wells, except possibly in some 
of the deeper valleys. In the large synclinal area east of Colorado Springs well water 
is obtainable at various depths in the Laramie and associated beds, a few ranches 
drawing their supplies from this source. A deep well at Calhan, described on page 72, 
failed to obtain satisfactory water supplies in the Laramie formation, and there was a 
similar experience with a well at Monument. 

In the Florence basin the Laramie formation lies at moderate depths and 
doubtless will prove to be water bearing. Some of the wells west of Florence 
obtained a moderate amount of water from this source, and in some of the coal mines 
there is sufficient water to be an obstacle to mining operations. 



84 ARKANSAS VALLEY IN EASTERN COLORADO. 

WATERS OF THE LATER TERTIARY DEPOSITS. 

In the wide areas covered by later Tertiary deposits abundant water supplies are 
usually obtainable for pump wells. The deposits consist of various materials which 
absorb a large proportion of the rainfall. This water sinks low in the deposits, and 
usually the largest amounts are found in the basal portions lying on the Pierre and 
Niobrara shales. Where the contact of the shales and overlying sands is exposed 
there are usually springs, by which a portion of the water escapes to the surface. 

Wells in the later Tertiary deposits vary in depth from 10 to 250 feet, the deepest 
ones being in the eastern portion of Cheyenne County. At Cheyenne Wells a large 
supply of excellent water is obtained at the base of the later Tertiary deposits at a 
depth of 257 feet. Ordinarily a large supply is found in these lower gravels, but it is 
well known among drillers that after the shale is reached it is useless to sink deeper. 

WATERS IN THE DUNE SANDS. 

Owing to their porous nature the dune sands absorb a large percentage of the 
water that falls upon them, and they usually lie in such manner as to intercept more 
or less of the surface run-off from the adjoining slopes. Accordingly they accumulate 
considerable water and afford excellent supplies for shallow wells throughout their 
area. 



INDEX. 



A. 

Page. 

Acanthopecten carboniferus, occurrence of 18 

Agriculture, Department of , wells of, records of... 58-59,68 

Allorisma subcuneatum, occurrence of 19 

Alluvium, occurrence and character of 35 

Altitudes, data on 8 

American Beet Sugar Company, well of, record of 53 

Amity, wells at and near, heads in.^ 77 

wells at and near, record of 65-66 

water of, analysis of 

yield of 78 

Analyses of water from Dakota formation 80-81 

Anchura (Drepanochilus) americana, occurrence of .. 31 

Anticlines, occurrence of 9 

Apishapa formation, character and occurrence of . . 13, 29-30 

fossilsof 30 

Apishapa River, canyon of, view of 10 

characterof 8 

Arapahoe formation, correlation of 33 

See also Poison Canyon formation. 

Archer, William, aid of 8 

Arikaree formation, deposition of 49 

occurrence of 12 

Arkansas River, altitudes on 8 

character of 8 

drainage basin of, map of 8 

valley of, geologic map of Pocket. 

view on 30 

Arlington, well near, head in 77 

well near, record of 63 

Artesian conditions, map showing Pocket. 

Artesian flows, area of 7,75 

area of, map showing Pocket. 

availability of 7 

Asiartella concentrica, occurrence of 18, 20 

Athyris subtilita, occurrence of 15 

Atlantosaurus fauna, occurrence of 21 

Avioulopecten occidentalis, occurrence of 20 

Ayer, wells at, record of 56 

wells at, water of, analyses of 80-81 

B. 

Baculites compressus, occurrence of 30, 31 

ovatus, occurrence of 31 

Badito formation, character and occurrence of 13, 18, 44 

Barela, well at, head in 77 

well at, record of 67 

Basins, occurrence of 9 

See aXso Florence basin. 

Baxter siding, well near, record of 72 

■ Bellerophon inspeciosus, occurence of 20 

percarinatus, occurrence of 18,20 

sp., occurrence of 18,19 



Page. 
Benton group, character and occurrence of. . 11, 13, 38, 40, 43 

deposition of 48 

section of, figure showing 51 

Blackwell ranch, well at, data on 59 

well at, head in 77 

Bloom, well at, head in 77 

well at, record of 56-57 

rocks in • 21 

water of, analyses of 80-81, 83 

BoggsFlat, well on, data of 61 

,Bolodont, occurrence of 20 

Bone-bearing sandstone, description of . . ; 22 

view of 22 

Boone, well at, record of 71 

C. 

Caddoa, wells at, head in 77 

wells at, record of 64 

water of, analysis of 80-81,83 

yield of 78 

Calhan, well at, record of 72-73, 83 

Cambrian rocks, fossils in 13, 14 

occurrence and character of 10, 13-14, 36-37 

Cambrian tune, history of 45 

Camerella, occurrence of 14 

Campophyllum torquium, occurrence of 18 

Canyon, bone-bearing sandstone near, view of 22 

Dakota sandstone near, vie ws of 12, 22 

Fremont limestone near, view of 16 

Harding sandstone near, views of 16, 42 

hogbacks at and near, views of 12 

Morrison formation near, view of 38 

section near 41 

views near 12, 16, 22, 38, 42 

wells at and near, data on 62 

Canyon embayment, description of 38-43 

geologic map and cross sections of, plate showing. 40 

Carboniferous rocks, occurrence and character of 10, 

13, 15-26 

Carboniferous time, history of 46-47 

Carlile formation, character and occurrence of 13, 

28,38,42-43,45 

fossils in 28 

view of ,. 32 

Cephalopods, occurrence of 31 

Chandler, section near 43 

well at, data on 62 

Cheyenne Wells, well at, record of 68 

wells at, water of 84 

Chonetes granulif era, occurrence of 20 

mesolobus, occurrence of 18, 20 

Chugwater formation, character and occurrence of. 13, 16, 37 

deposition of 46-47 

See also Red Beds. 

85 



86 



INDEX. 



Page. 

Clark's mineral springs, water of 59 

Colorado, eastern, geology of 9-12 

rocks in 10-12 

structure of 9 

topography of 8 

Colorado City, Red Beds at, view of 38 

section at 17 

well at, data on 72 

Colorado Coal and Iron Co., well of, data on 60 

well of, water of, analysis of 80-81 

Colorado Southern Railroad Co., well of, data on 67-68 

Columbia Heights, Pueblo, well at, record of 60 

Comanche series, character and occurrence of 13, 25 

deposition of 48 

fo-ssils in 25 

Cooper well, record of 58 

Creamy sandstone. See Tensleep sandstone. 

Cretaceous formations, character of .'. 13 

descriptions of 21-34 

occurrence of 10-12 

outcrops of 9,12 

Cretaceous time, history of 47-48 

Crosby, W. 0., on Manitou embayment 36, 

Cross, Whitman, on Dakota sandstone 26 

on igneous rooks 35 

on Ordovician rocks 14 

on Red Beds 17 

Cuchara, well at, data on 70 

Cuchara formation, character and occurrence of 13,34 

deposition of 49 

Culebra Range, section of 19 

Cunningham, A. A., analysis by 80-81 

D. 

Dakota formation, artesian wells from, area of 75-76 

character of 7,10,13,25-27,40-44 

configuration of 7 

deposition of ". 47-48 

depth to 74-75 

map showing Pocket. 

fossUsof 26 

hogbacks of , views of 12,22 

occurrence of 7,11,25-27,38,40-44 

outcrops of 9,11 

relations of other rocks and, map and cross sec- 
tions showing 86,40,46 

structure of, map showing 56 

sections of, figures showing 14, 40, 51 

strata above, section of, figure showing 51 

water hole in, view of 44 

water of, analyses of 80-81 

depth to, map showing Pocket. 

derivation of 7 

head of 50,76-77 

map showing 76 

leakage of 50, 52 

occurrence of 50-82 

quality of 79-82 

quantity of 77-78 

source of 73-74 

wells to 52,68 

Dalmanella testudinaria, occurrence of 15 

Dearborn Drug Co., analysis by 80,81 

Delhi, well at, head in 77 

well at, record of 66 

water of, analysis of 80-81 

Denver, bcisin at 9 



Page. 

Denver and Rio Grande Railroad, analysis by 80-81 

Denver formation, correlation of 34 

See also Cuchara formation: 

Derbya crassa, occurrence of 19, 20 

Devonian rocks, occurrence of 10 

Devonian time, history of 46 

Didymoeeras cochleatum, occurrence of 31 

nebrasoense, occurrence of 31 

Dinosaur, occurrence of 33 

Drainage, description of 8 

map showing 8 

Drepanochilus americana, occurrence of 31 

Dune sands, occurrence of 35 

water in 84 

Eldridge, G. H., on Morrison formation 21 

Elmore, well at, data on 70 

Embayments, location of 9 

See also Canyon embayment, Manitou embayment. 

Emmons, S. F., on Cambrian history 45 

Endlich, F. M., on Culebra Range 18 

Kuphemus carbonarius, occurrence of 18 

Exiteloceras cheyennense, occurrence of ^31 

F. 

Fariss House, Pueblo, well of, data on 60 

well of, head in 77 

water of, analysis of 80-81 

Field work, extent of , 8 

Fisher, C. A., fossils found by 34 

work of 8 

Flexures, description of 9 

Florence, basin at 9 

basin at, wells in .' 83 

wells at and near, data on 73 

head in 77 

records of 61 

water of, analysis of 81 

Formations, descriptions of 10-35 

stratigraphic table of 13 

Fort Lyon, well at, head in 77 

well at, record of 58-59 

Fountain formation, character of 13, 17-18, 37, 39 

description of 10 

occurrence of 17-18,37,39-44 

vertical beds of, view of 18 

See also Red Beds. 

Fowler, well at, record of 54 

Fox Hills formation, character and occurrence of 12,32 

deposition of 48 

fossils of 32 

water of 83 

Franceville Junction, well at, data on 73 

Fremont limestone, character of 13, 14, 39 

fossils in 14, 39 

occurrence of 14, 39-43 

view of 16 

Fucoid halymenites, occurrence of 32 

Fuson formation, correlation of 11 

G. 

Garden of Gods, Red Beds in, view of 18 

section near 17 

Garden Park area, rocks in 39-40 

Ganger, J. E., well of, record of 55-56 



INDEX. 



87 



Page. 

Geologic history, narrative of 45-50 

Geologic sections, figures showing 14, 36 

Geology of Arkansas Valley region, description of 12-50 

of eastern Colorado, description of 10-12 

Gilbert, G. K., fossils collected by 31 

on Dakota sandstone 26 

on igneous rocks 36 

on Morrison formation 23 

on Nussbaum formation : 34 

on Red Beds 17-18,21,23 

work of 7 

Glauconiie, occurrence of \ 86 

Glen Eyrie, Colo., sectionsnear 15,17 

Grabau, A. W., fossils found by 15,37 

Granada, wells at, head in 77 

wells at, record of 65 

water of, analysis of 80-81 

yield of 78 

Grand Hotel, Pueblo, well of, data on 60 

well of, head in 77 

water of, analysis of 80-81 

quality of 79 

Graneros shale, character and occurrence of. . 13, 27, 88, 42, 45 

Grape Creek, Morrison formation on, view of 38 

Great Plains, view on 8 

Greenhorn limestone, character of 13, 27-28 

fossils in 28,42 

views of 28 

occurrence of 28,38,42-43 

view of 26 

Greenhorn Mountain, rocks on 43-45 

rocks on, map showing 46 

Gryphsea corrugata, occurrence of ! 25 

Gypsum, deposition of 46-47 

occurrence of 17,79 

H. 

Halysites catenulatus, occurrence of 14, 39 

Harding sandstone, character of 13, 14, 39 

fossils in 14 

occurrence of 14, 39^3 

quarry in, view of 16 

views of 16,42 

Harding's quarry, section at 41 

Hatcher J. B. , on Morrison formation 22 

Hayden, F. V., on Manitou embayment 36 

Haystack Butte, view of 10 

Head of artesian water, amount of 50-51, 76-77 

map showing 76 

Heteroceras (Exiteloceras) cheyennense, occurrence 

of 31 

(Didymoceras) cochleatum, occurrence of 31 

(Didymoceras) nebrascense, occurrence of .... 31 

sp., occurrence of 81 

High Plains in Colorado, map of 8 

Hillebrand, W. P., analyses by 31,80-81 

Hills, R. C, on Badito formation 18,44 

on Dakota formation 26-27 

on igneous rocks 36 

on Morrison formation 23 

Hoehne, well at, data on 69 

Hogbacks, views of 12,18 

Holbrook, well at, data on 56 

well at, head in 76-77 

Holly, well at, data on 66 



Page. 

Horse Creek, well on, record of 59 

Huerfano formation, character of 13 

deposition of 49 

Huerfano River, character of 8 

Hustedia mormoni, occurrence of 19, 20 

Hydrostatic grade, definition of 50,52 

figure showing '. 52 

I. 

Igneous rocks, distribution of, plate showing Pocket. 

occurrence of 9, 35-36 

Inoceramus, occurrence of 22,29 

crispii' var. barabini, occurrence of 31 

deformis, occurrence of 29 

labiatus, occurrence of 28, 38, 42 

view of 28 

sagensis, occurrence of 31 

vanuxemi, occurrence of 31 

Iron Springs. See Bloom. 

J. 

Jurassic rocks, occurrence of 10-U 

K. 

Kansas Pacific Railway, well of, data on 69 

Kit Carson, well at, data on 69 

1.. 

La Junta, Carlile sandstone near, view of 32 

ridge near, well on, view of 54 

Timpas limestone in quarry near, view of 26 

wells at '. 76 

head in 76 

records of 54-55 

rocks in 21 

water of, analysis of 80-83 

yield of • 78 

Lakota formation, correlation of 11 

deposition of 47-48 

Lamar, wells at, data on 64, 76 

wells at, head in .'. 77 

record of 64-66 

water of, analysis of 80-81 

yield of 78 

Laramie formation, character of 12, 13, 32-33 

coals In 32-33 

occurrence of 9,12,32,38,40,43 

waterof 83 

Las Animas, wells at and near, head in 77 

wells at and near, records of 57-59, 63-64 

water of, analysis of 80-81 

yield of 78 

Leakage, eif ect of, on artesian wells 50, 52, 75, 77-78 

effect of, figure showing 52 

Lee, W. T., fossils collected by 18 

on Cambrian rocks 14,37 

on Comanche series 25 

on Morrison formation 23-25 

on Ordovician rocks 15 

sections by 19,23,24 

work of 8 

Lenox well.dataon 55 

Lida bellistriata, occurrence of 18 



88 



INDEX. 



Page. 
Lingula, occurrence of 26 

pinnoeformis, occurrence of 13 

Lingulepsis sp., occurrence of 13 

Lower Wyoming beds. See Fountain formation. 

Lucina occidentalis, occurrence of 30-31 

occidentalis var. ventricosa, occurrence of 31 

Lyken« formation. See Upper Wyoming beds. 
Lyons sandstone. See Tensleep sandstone. 

M, 

McLane, information from 68 

McLane well, data on 61 

JfcNeen well, data on ' 55 

JicVay, C. H., aid of 8,53,56 

Manitou embayment, description of 36-38 

geologic map of 36 

rocks in 36-38 

sections of, plate showing 36 

Manitou limestone, character of 13-14, 37, 39 

fossils in 14 

occurrence of 13-15,37,39-40 

Manzanola, wells at, head in 76-77 

wells at, records of 53 

yield of 78 

Map of artesian conditions in Arkansas Valley Pocket. 

of central-western United States 7 

of drainage basin of Arkansas River 8 

showing head of water in Dakota sandstone 76 

showing structure of Dakota sandstone 56 

Map, geologic, of Arkansas Valley Pocket. 

of Canyon embayment 40 

of Manitou embayment 36 

of Wet Mountains 46 

Marlaman well, record of 59 

Mesa de Maya, location of 8 

rocks of 36 

Millsap limestone, character and occxirrence of 13, 

15-16, 20, 39, 43 

deposition of 46 

fossils in 15 

Mineral Park, well of, data on 60 

well of, water of, analysis of 80 

Minnekahta limestone, occurrence of 16-17 

Miocene time, history of 49 

Mississippian rocks, character of 13 

Monument, well at, data on 73,83 

Monument Creek formation, character and occurrence 

of 12-13,34 

deposition of 49 

fossils of 34 

Morrison formation, bone-bearing sandstone in 22 

bone-bearing sandstone in, view of 22 

character and occurrence of 11, 13, 21-25, 38-40, 42-44 

deposition of 47-48 

fossils in 21-22, 397 

section of 23 

figure showing 61 

view of . . , 38 

water of, analysisof 83 

quality of 82 

Murchisonia copei, occurrence of 18 

N. 

Naticopsls altonensis, occurrence of 18 

altonensis var. gigantea, occurrence of 18 

Nautilus dekayi, occurrence of '. 31 



Page. 

Nepesta, tepee buttes near, view of 32 

Niobrara chalk, character and occurrence of 11, 38 

deposition of 48 

fossils of, views of 28 

section of, figure showing «-. 51 

North Pueblo Heights, well at, data on 61 

Nucula ventricosa, occurrence of 18 

Nussbaum formation, character and occurrence of. 13, 34-35 

deposition of 49 

sand from 35 

Ny burg siding, well near, record of 72 

O. 

Obolus similis,' occurrence of 36 

Ogalalla-Nussbaum beds. See Nussbaum formation. 

Oil Creek, rocks on 39 

Oligocene rocks, deposition of 49 

occurrence of 12 

Opileta, occurrence of 14 

Orbiculoidea convexa, occurrence of 18 

missouriensis, occurrence of 18 

sp., occurrence of. 20 

Ordovician formations, character and occurrence of.. 13-15 

descriptions of 14-15 

occurrence of 10, 39-43 

section of 15 

Ordovician time, history of 46 

Ordway, well at, head in 77 

well at, record of ~. 62-63 

well near, record of 63 

Orthoceras sp., occurrence of 18,20 

Ostrea congesta, occurrence of 29-30 

congesta, view of 28 

glabra, view of 33 

inornata, occurrence of 31 

P. 

Patellostium montfortianum, occurrence of 18 

Peale, A. C, on Manitou embayment 36 

section by 15 

PelecjTpod, occurrence of 18 

Pennsy 1 vanian rocks, character of 13 

Pennsylvanian time, history of 46 

Permian time, history of 46-47 

Phillipsia sp., occurrence of 19 

Pierre shale, character and occurrence of 11, 13, 

30-31, 42-43 

deposition of 48 

fossils in 30-31 

oil in 11 

section of, figure showing 51 

tepee buttes in 30-31 

limestone of, analysisof 31 

view of 32 

Plains, marl, occurrence of 34 

Pleurotomaria perizomata, occurrence of 18 

sp., occurrence of 18 

Pliocene rocks, deposition of 49 

occurrence of 12 

Plum Creek, well on, data on 59, 76 

well on, head in 77 

canyon of, sections in 20-21, 23-24 

Poison Canyon formation,character and occurrence of. 13, 33 

deposition of 49 

fossils of 33-34 



INDEX. 



89 



Page. 

Portland, well near, view of 62 

wells at, data on 62 

head in 77 

yield of 78 

Post-Laramie time, history of 49-50 

Powers, W. A., analyses by 80-83 

Pressure. See Head. 

Prionocyclas wyomingensis, occurrence of 28 

Productus cora, occurrence of ..18,20 

costatus, occurrence of 18 

longispinus, occurrence of 18 

nebrascensis, occurrence of 20 

Ptychoparia, occurrence of 13,39 

Ptychoceras crassum, occurrence of 31 

Pueblo, wells at and near, head in 76-77 

wells at and near, records of 59-61,72 

water of, analyses of 80-81 

quality of 79 

Pugnellus, occurrence of 28 

Purgatory River, description of 8 

stonewall on, views of 18,24 

Q. 

Quaternary deposits, character of 12,13,36 

occurrence of 35 

Quaternary time, history of 50 

B. 

Eaton Mesa, location of 8 

rocks of 36 

Red Beds, character and occurrence of 10, 16-21, 40, 42 

correlation of 21 

fossils in 18-20 

deposition of 46 

divisions of 10 

conglomerate at base of, view of 42 

occurrence of 10 

sections of 17, 19-21 

figure showing 51 

water of, analyses of 83 

quality of 82 

views of 18,38 

Red Rock Canyon, section in 24 

Relief map of Arkansas River Valley 8 

Ritchie Creek, well on, data on 62 

Rocky Ford, well at, view of 54 

wells at, head in 76-77 

records of 52-53 

water in, analysis of 80-82 

quantity of 78 

Rotella verrucelif era, occurrence of 18 

Rouse Junction, well at, head in 77 

well at, records of 69-70 

water of, analysis of 

yield of 78 

Rusty zone, character of 30 

St. Mary, well at, data on 62 

well at, water of, quality of 62,79 

Salt Creek, well at, head in 77 

well at, record of...: 70-71 

water of , analysis of 80-81 

yield of 78 

Sanitarium, well of, data on 62 

Saurians, occurrence of 22,24,34,47-48 



Page. 
Scaphites nodosus, occurrence of 31 

nodosus var. quadrangularis, occurrence of 31 

var. bre vis, occurrence of 31 

Schizodus wheeleri, occurrence of 19, 20 

Sections, geologic, across Colorado, figures showing . . 14 

Selenite, occurrence of 30 

Seminula argentea, occurrence of 18, 20 

Sheridan Lake, well at, data on 69 

well at, head in 77 

Siebenthal, C. E., section by 43 

work of 8 

Silurian rocks, absenceof 10 

Silurian time, history of 46 

Small, C. H., well of, record of 60-61 

Smith, W. S. T., workof 8 

Soda sulphate, occurrence of 79 

Soleniscus bre vis, occurrence of .• 18 

sp., occurrence of 18,20 

South Platte River, character of 8 

South Pueblo, well at, record of 59-60 

Spanish Peaks, basin near 9 

Sphaerodoma texana, occurrence of 18 

sp., occurrence of 18 

Spirifer cameratus, occurrence of '. 18, 20 

centionatus, occurrence of 15 

rockymontana, occurrence of 15-16, 18, 43 

Squamularia perplexa, occurrence of 18, 20 

Stanton, T. W., fossils determined by 31 

fossils found by 11,26 

on Comanche series 25 

Stonewall, views of 18,24 

Straparollus catilloides, occurrence of 18 

Stratigraphy, description of 12-35 

Streams, data on 8 

Structure, description of 9 

map showing 56 

Sugar Beet and Irrigated Land Co., well of, record of. 66 

Sugar City, well at, data on 63 

Syringopora sp., occurrence of 18 

T. 

Temnocheilus winslowi, occurrence of 19 

Tensleep sandstone, character and occurrence of . . 10, 13, 37 

Tepee buttes, limestone in, analysis of 31 

occurrence of 30, 31 

view of 32 

Tertiary formations, character of 13 

descriptions of 34-35 

occurrence of 9-10, 12 

water of 84 

Tertiary grit, occurrence of 34 

Tertiary time, history of 48-49 

Thatcher, Greenhorn limestone near, view of 26 

water hole near, view of 44 

well at, data on 69 

wells near, records of 66-67 

Thetis circularis, occurrence of 31 

Timpas, well at, head in 77 

record of 56 

water of, analysis of 80, 81 

Timpas limestone, character of 13, 28-29 

fossils of , 29 

occurrence of 28, 38, 40, 42-43 

views of 26, 32 

Titanotherium, occurrence of 34 

Trachydomia wheeleri, occurrence of 18 



90 



INDEX. 



Page. 

Triassic rocks, character and occurrence of 10, 13 

Trinidad, stone wall near, views of 18, 24 

well at, head in 77 

record of 67 

Trinidad sandstone, character of 13 

Troy, wellat 69 

Two Butte, igneous intrusion at 9, 36 

view of 44 

Tyrone, well at, record of 66-67 

well at, water of, analysis of 80-81 

V. 

Unio, occurrence of 33 

United States, west-central, index map of 7 

Upper Wyoming beds, correlation of 21 

occurrence of 16-17 

V. 

VetaPass, fossils from 19-20 

Von Schultz & Low, analysis by 80-81 

W. 

Walcott, C. D., fossil determined by 36 

on Ordovician rocks 14 

section by 41 

Walsenburg, well at, data on 70 

Water, underground, analyses of 80-81 

depth to 74-75 

map showing Pocket. 

derivation of 7, 73-74 



Page. 

Water, description of 50-84 

head of 50-51,76-77 

map showing 76 

occurrences of, description of 50-84 

quality of 80-82 

quantity of 77-79 

Water hole, view of 44 

Watervale, well at, data on 67-68 

Weller^ Stuart, fossils examined by 15, 18 

Wells, H.L., analyses by 80-81 

Wells, artesian, area of 75-76 

descriptions of 52-68 

development of 7 

head in 76-77 

relations of, map showing 50 

vie ws of 54, 62 

Wells, dry, descriptions of 68-73 

Wells, flowing, descriptions of 52-62 

Wells, nonflowing, descriptions of 62-68 

Wet Mountains, rocks on, map and cross sections of . . 46 

Wetmore, wellat, data on 68 

well near, head in*. 77 

White, C. A., on Morrison fossils 22 

White River group, deposition of 49 

occurrence of 12 

WykofE Park, wellat, data on 53 

Wyoming formation, correlation of 21 

z. 

Zaphrentis sp., occurrence of 18,20 



CLASSIFICATION OF THE PUBLICATIONS OF THE UNITED STATES GEOLOGICAL SURVEY. 

[Professional Paper No. 52.] 

The serial publications of the United States Geological Survey consist of (1) Annual Reports, 
(2) Monographs, (3) Professional Papers, (4) Bulletins, (5) Mineral Resources, (6) Water-Supply 
and Irrigation Papers, (7) Topographic Atlas of the United States — folios and separate sheets thereof, 
(8) Geologic Atlas of the United States — folios thereof. The classes numbered 2, 7, and 8 are sold 
at cost of publication; the others are distributed free. A circular giving complete lists may be had 
on application. 

Most of the above publications may be obtained or consulted in the following ways: 

1. A limited number are delivered to the Director of the Survey, from whom they may be 
obtained, free of charge (except classes 2, 7, and 8), on application. 

2. A certain number are allotted every Member of Congress, from whom they may be obtained, 
free of charge, on application. 

3. Other copies are deposited with the Superintendent of Documents, Washington, D. C , from 
whom they may be had at practically cost. 

4. Copies of all Government publications are furnished to the principal public libraries in the 
large cities throughout the United States, where they may be consulted by those interested. 

The Professional Papers, Bulletins, and Water-Supply Papers treat of a variety of subjects, and 
the total number issued is large. They have therefore been classified into the following series: A, 
Economic geology; B, Descriptive geology; C, Systematic geology and paleontology; D, Petrography 
and mineralogy; E, Chemistry and physics; F, Geography; G, Miscellaneous; H, Forestry; I, Irriga- 
tion; J, Water storage; K, Pumping water; L, Quality of water; M, General hydrographic investiga- 
tions; N, Water power; 0, Underground waters; P, Hydrographic progress reports. This paper 
is the eighty-ninth in Series B, and the fifty-fifth in Series O, the complete lists of which follow. 
(PP=Professional Paper, B=Bulletin, WS=Water-Supply Paper.) 

SERIES B, DESCRIPTIVE GEOLOGY. 

B 23. Observations on the junction between the Eastern sandstone and the Keweenaw series on Keweenaw Point, Lake 
Superior, by R. D. Irving and T. C. Chamberlin. 1885. 124 pp., 17 pis. (Out of stock.) 

B 33. Notes on geology of northern California, by J. S. Diller. 1886. 23 pp. (Out of stock.) 

B 39. The upper beaches and deltas of Glacial Lake Agassiz, by Warren Upham. 1887. 84 pp., 1 pi. (Out of stock.) 

B 40. Changes in river courses in Washington Territory due to glaciation, by Bailey Willis. 1887. 10 pp., 4 pis. (Out of 
stock.) , 

B 45. The present condition of knowledge of the geology of Texas, by R. T. Hill. 1887. 94 pp. (Out of stock.) 

B 53. The geology of Nantucket, by N. S. Shaler. 1889. 55 pp., 10 pis. (Out of stock. ) 

B 57. A geological reconnaissance in southwestern Kansas, by Robert Hay. 1890. 49 pp., 2 pis. 

B 58. The glacial boundary in western Pennsylvania, Ohio, Kentucky, Indiana, and Illinois, by G. F. Wright, with intro- 
duction by T. G. Chamberlin. 1890. 112 pp., 8 pis. (Out of stock. ) 

B 67. The relations of the traps of the Newark system in the New Jersey region, by N. H. Darton. 1890. 82 pp. (Out of 
stock.) 

B 104. Glaciation of the Yellowstone Valley north of the Park, by W. H. Weed. 1893. 41 pp., 4 pis. 

BIOS. A geological reconnaissance in central Washington, by I. C. Russell. 1893. 108 pp., 12 pis. (Out of stock.) 

B 119. A geological reconnaissance in northwest Wyoming, by G. H. Eldridge. 1894. 72 pp., 4 pis. 

B 137. The geology of the Fort Riley Military Reservation and vicinity, Kansas, by Robert Hay. 1896. 35 pp., 8 pis. 

B 144. The moraines of the Missouri Coteau and their attendant deposits, by J. E. Todd. 1896. 71 pp., 21 pis. 

B 168. The moraines of southeastern South Dakota and their attendRit deposits, by J. E. Todd. 1899. 171 pp., 27 pis. 

B 159. The geology of eastern Berkshire County, Massachusetts, by B. K. Emerson. 1899. 139 pp., 9 pis. 

B 165. Contributions to the geology of Maine, by H. S. Williams and H. E. Gregory. 1900. 212 pp., 14 pis. 

I 



II SERIES LIST. 

WS 70. Geology and water resources of the Patrick and Goshen Hole quadrangles In eastern Wyoming and western 
Nebraska, by G. I. Adams. 1902. 50 pp., 11 pis. 

B 199. Geology and water resources of the Snake River Plains of Idaho, by I. C. Russell. 1902. 192 pp., 25 pis. 

PP 1. Preliminary report on the Ketchikan mining district, Alaska, with an introductory sketch of the geology of south- 
eastern Alaska, by A. H. Brooks. 1902. 120 pp., 2 pis. 

PP 2. Reconnaissance of the northwestern portion of Seward Peninsula, Alaska, by A. J. Collier. 1902. 70 pp., 11 pis. 

PP 3. Geology and petrography of Crater Lake National Park, by J. S. Diller and H. B. Patton. 1902. 167 pp., 19 pis. 

PP 10. Reconnais-sance from Fort Hamlin to Kotzebue Sound, Alaska, by way of Dall, Kanuti, Allen, and Kowak rivers, 
by W. C. Mendenhall. 1902. 68 pp., 10 pis. 

PP 11. Clays of the United States east of the Mississippi River, by Heinrich Ries. 1903. 298 pp., 9 pis. 

PP 12. Geology of the Globe copper district, Arizona, by F. L. Ransome. 1903. 168 pp., 27 pis. 

PP 13. Drainage modifications in southea-stern Ohio and adjacent parts of West Virginia and Kentucky, by W. G. Tight. 
1903. Ill pp., 17 pis. 

B 208. Descriptive geology of Nevada south of the fortieth parallel and adjacent portions of California, by J. E. Spurr. 

1903. 229 pp., 8 pis. 

B 209. Geology of Ascutney Mountain, Vermont, by R. A. Daly. 1903. 122 pp., 7 pis. 

WS 78. Preliminary report on artesian basins in southwestern Idaho and southeastern Oregon, by I. C. Russell. 1903. 

51 pp., 2 pis. 
PP 15. Mineral resources of the Mount Wrangell district, Alaska, by W. C. Mendenhall and F. C. Schrader. 1903. 71 pp., 

10 pis. 
PP 17. Preliminary report on the geology and water resources of Nebraska west of the one hundred and third meridian, 

by N. H. Darton. 1903. 69 pp., 43 pis. 
B 217. Notes on the geology of southwestern Idaho and southeastern Oregon, by I. C. Russell. 1903. 83 pp., 18 pis. 
B 219. The ore deposits of Tonopah, Nevada (preliminary report) , by J. E. Spurr. 1903. 31 pp., 1 pi. 
PP 20. A reconnaissance in northern Alaska in 1901, by F. C. Schrader. 1904. 139 pp., 16 pis. 

PP 21. The geology and ore deposits of the Bisbee quadrangle, Arizona, by F. L. Ransome. 1904. 168 pp., 29 pis. 
WS 90. Geology and water resources of part of the lower James River Valley, South Dakota, by J. E. Todd and C. M. Hall. 

1904. 47 pp., 23 pis. 

PP 25. The copper deposits of the Encampment district, Wyoming, by A. C. Spencer. 1904. 107 pp., 2 pis. 

PP 26. Economic resources of the northern Black Hills, by J. D. Irving, with contributions by S. F. Emmons and T. A. 

Jaggar, jr. 1^04. 222 pp., 20 pis. 
PP 27. A geological reconnaissance across the Bitterroot Range and Clearwater Mountains in Montana and Idaho, by 

Waldemar Lindgren. 1904. 122 pp., 15 pis. 
PP 31. Preliminary report on the geology of the Arbuckle and Wichita mountains in Indian Territory and Oklahoma, 

by J. A. Taff, with an appendix on reported ore deposits in the Wichita Mountains, by H. F. Bain. 1904. 97 pp., 

8 pis. 
B 235. A geological reconnaissance across the Cascade Range near the forty-ninth parallel, by G. O. Smith and F. C. 

Calkins. 1904. 103 pp., 4 pis. 
B 236. The Porcupine placer district, Alaska, by C. W. Wright. 1904. 35 pp., 10 pis. 
B 237. Igneous rocks of the Highwood Mountains, Montana, by L. V. Pirsson. 1904. 208 pp., 7 pis. 
B 238. Economic geology of the lola quadrangle, Kansas, by G. I. Adams, Erasmus Ha worth, and W. R. Crane. 1904. 

83 pp., 1 pi. 
PP 32. Geology and underground water resources of the central Great Plains, by N. H. Darton. 1905. 433 pp., 72 pis. 
WS 110. Contributions to hydrology of eastern United States, 1904; M. L. Fuller, geologist in charge. 1905. 211 pp., 5 pis. 
■ B 242. Geology of the Hudson Valley between the Hoosic and the Kinderhook, by T. N. Dale. 1904. 63 pp., 3 pis. 
PP 34. The Delavan lobe of the Lake Michigan Glacier of the Wisconsin stage of glaciation and associated phenomena, by 

W. C. Alden. 1904. 106 pp., 15 pis. 
PP 35. Geology of the Perry Basin in southeastern Maine, by G. O. Smith and David White. 1905. 107 pp., 6 pis. 
B 243. Cement materials and industry of the United States, by E. C. Eckel. 1905. 395 pp., 15 pis. 
B 246. Zinc and lead deposits of northeastern Illinois, by H. F. Bain. 1904. 56 pp., 5 pis. 
B 247. The Fairhaven gold placers of Seward Peninsula, Alaska, by F. H. Moffit. 1905. 85 pp., 14 pis. 
B 249. Limestones of southwestern Pennsylvania, by F. G. Clapp. 1905. 52 pp., 7 pis. 
B 250. The petroleum fields of th& Pacific coast of Alaska, with an account of the Bering River coal deposit, by G. C. 

Martin. 1905. 65 pp., 7 pis. 
B 251. The gold placers of the Fortymile, Birch Creek, and Fairbanks regions, Alaska, by L. M. Prindle. 1905. 64 pp. 

16 pis. 
WS. 118. Geology and water resources of a portion of east-central Washington, by F. C. Calkins. 1905. 96 pp., 4 pis. 
B 252. Preliminary report on the geology and water resources of central Oregon, by I. C. Russell. 1905. 138 pp., 24 pis. 
PP 36. The lead, zinc, and fluorspar deposits of western Kentucky, by E. 0. Ulrich and W. S. Tangier Smith. 1905. 

218 pp., 15 pis. 
PP 38. Economic geology of the Bingham mining district of Utah, by J. M. Boutwell, with a chapter on areal geology, by 

Arthur Keith, and an introduction on general geology, by S. F. Emmons. 1905. 413 pp., 49 pis. 
PP 41. The geology of the central Copper River region, Alaska, by W. C. Mendenhall. 1905. 133 pp., 20 pis. 
B 254. Report of progress in the geological resurvey of the Cripple Creek district, Colorado, by Waldemar Lindgren and 

F. L. Ransome. 1904. 36 pp. ^ 

B 255. The fluorspar deposits of southern Illinois, by H. Foster Bain. 1905. 75 pp., 6 pis. 
B 256. Mineral resources of the Elders Ridge quadrangle, Pennsylvania, by R. W. Stone. 1905. 85 pp., 12 pis. 
B 257. Geojogy and paleontology of the Judith River beds, by T. W. Stanton and J. B. Hatcher, with a chapter on the 

fossil plants, by F. H. Knowlton. 1905. 174 pp., 19 pis. 



SERIES LIST. Ill 

PP 42. Geology of the Tonopah mining district, Nevada, by J. E. Spurr. 1905 295 pp., 24 pis. 

WS 123. Geology and underground water conditions of the Jornada del Muerto, New Mexico, by C. R. Keyes. 1905. 

42 pp., 9 pis. 
WS 136. Underground waters of Salt River Valley, Arizona, by W. T. Lee. 1905. 194 pp., 24 pis. 
PP 43. The copper deposits of Clifton-Morenci, Arizona, by Waldemar Lindgren. 1905. 375 pp., 25 pis. 
B 265. Geology of the Boulder district, Colorado, by N. M. Fenneman. 1905. 101 pp., 5 pis. 
B 267. The copper deposits of Missouri, by H. F. Bain and E. 0. Ulrich. 1905. 52 pp., 1 pi. 

PP 44. Underground water resources of Long Island, New York, by A. C. Veatch and others. 1905. 394 pp., 34 pis. 
WS 148. Geology and water resourc. s of Oklahoma, by C. N. Gould. 1905. 178 pp., 22 pis. 
B 270. The configuration of the rock floor of Greater New York, by W. H. Hobbs. 1905. 96 pp., 5 pis. 
B 272. Taconic physiography, by T. M. Dale. 1905. 52 pp., 14 pis. 
PP 45. The geography and geology of Alaska, a summary of existing knowledge, by A. H. Brooks, with a section on cliinate, 

by Cleveland Abbe, jr., and a topographic map and description thereof, by R.M. Goode. 1905. 327 pp., 34 pis. 
B 273. The drumlins of southeastern Wisconsin (preliminary paper), by W.C.Alden. 1905. 46 pp., 9 pis. 
PP 46. Geology and underground water resources of northern Louisiana and southern Arkansas, by A. C. Veatch. 1906, 

— pp., 51 pis. 
PP 49. Geology and mineral resources of part of the Cumberland Gap coal field, Kentucky, by G. H. Ashley and L. C. Glenn, 

In cooperation with the State Geological Department of Kentucky, C.J. Norwood, curator. 1906. 239 pp. , 40 pis. 
PP 50. The Montana lobe of the Keewatin ice sheet, by F. H. H. Calhoun. 1906. 62 pp., 7 pis. 
B. 277. Mineral resources of Kenai Peninsula, Alaska: Gold fields of the Turnagain Arm region, by F. H. MoflBt, and the 

coal fields of Kachemak Bay region, by R. W. Stone. 1906. 80 pp., 18 pis. 
WS 154. The geology and water resources of the eastern portion of the Panhandle of Texas, by C. N. Gould. 1906. 

64 pp., 15 pis. 
B 278. Geology and coal resources of the Cape Lisburne region, Alaska, by A. J. Collier. 1906. 54 pp., 9 pis. 
B 279. Mineral resources of the Kittanning and Rural Valley quadrangles, Pennsylvania, by Charles Butts. 1906. — pp. 

11 pis. 
B 280. The Rampart gold placer region, Alaska, by L. M. Prindle and F. L. Hess. 1906. 54 pp., 7 pis. 
B 282. Oil fields of the Texas-Louisiana Gulf coastal plain, by N. M. Fenneman. 1906. 146 pp., 11 pis. 
WS 157. Underground water in the valleys of Utah Lake and Jordan River, Utah, byG. B. Richardson. 1906. 81 pp., 9 pis. 
PP 51. Geology of the Bighorn Mountains, by N. H. Darton. 1906. 129 pp., 47 pis. 
WS 158. Preliminary report on the geology and underground waters of the Roswell artesian area. New Mexico, by C. A. 

Fisher. 1906. 29 pp., 9 pis. 
PP 52. Geology and underground waters of the Arkansas Valley in eastern Colorado, byN. H. Darton. 1906. 90 pp., 28 pis. 

SERIES O, UNDERGROUND WATERS. 

WS 4. A reconnaissance in southeastern Washington, by I. C. Russell. 1897. 96 pp., 7 pis. (Out of stock.) 

WS 6. Underground waters of southwestern Kansas, by Erasmus Haworth. 1897. 65 pp., 12 pis. (Out of stock.) 

WS 7. Seepage waters of northern Utah, by Samuel Fortier. 1897. 50 pp., 3 pis. (Out of stock.) 

WS 12. Underground waters of southeastern Nebraska, by N. H. Darton. 1898. 56 pp., 21 pis. (Out of stock.) 

WS 21. Wells of northern Indiana, by Frank Leverett. 1899. 82 pp., 2 pis. (Out of stock. ) 

WS 26. Wells of southern Indiana (continuation of No. 21), by Frank Leverett. 1899. 64 pp. (Out of stock.) 

WS 30. Water resources of the Lower Peninsula of Michigan, by A. C. Lane. 1899. 97 pp., 7 pis. (Out of stock.) 

WS 31. Lower Michigan mineral waters, by A. C. Lane. 1899. 97 pp., 4 pis. (Out of stock.) 

WS 34. Geology and water resources of a portion of southeastern South Dakota, by J. E. Todd. 1900. 34 pp., 19 pis. 

WS 53. Geology and water resources of Nez Perces County, Idaho, Pt. I, by I. C. Russell. 1901. 86 pp., 10 pis. < 

WS 54. Geology and water resources of Nez Perces County, Idaho, Pt. II, by I. C. Russell. 1901. 87-141 pp. 

WS 55. Geology and water resources of a portion of Yakima County, Wash., by G. 0. Smith. 1901. 68 pp., 7 pis. 

WS 57. Preliminary list of deep borings in the United States, Pt. I, by N. H. Darton. 1902. 60 pp. (Out of stock.) 

WS 59. Development and application of water in southern California, Pt. I, by J. B.Lippincott. 1902. 95 pp., 11 pis. (Out 

of stock. ) 
WS 60. Development and application of water in southern California, Pt. II, by J. B. Lippincott. 1902. 96-140 pp. (Out of 

stock.) 
WS 61. Preliminary list of deep borings in the United States, Pt. II, by N. H. Darton. 1902. 67 pp. (Out of stock.) 
WS 67. The motions of underground waters, by C. S. Slichter. 1902. 106 pp., 8 pis. 

B 199. Geology and water resources of the Snake River Plains of Idaho, by I. C. Russell. 1902. 192 pp., 25 pis. 
WS 77. Water resources of Molokai, Hawaiian Islands, by Waldemar Lindgren. 1903. 62 pp., 4 pis. 
WS 78. Preliminary report on artesian basins in southwestern Idaho and southeastern Oregon, by I. C. Russell. 1903. 

53 pp., 2 pis. 
PP 17. Preliminary report on the geology and water resources of Nebraska west of the one hundred and third meridian, 

by N. H. Darton. 1903. 69 pp., 43 pis. 
WS 90. Geology and water resources of a part of the lower James River Valley, South Dakota, by J. E. Todd and C. M. Hall. 

1904. 47 pp., 23 pis. 
WS 101. Underground waters of southern Louisiana, by G. D. Harris; with discussions of their uses for water supplies and 

for rice irrigation, by M. L. Fuller. 1904. 98 pp., 11 pis. 
WS 102. Contributions to the hydrology of eastern United States, 1903, by M. L. Fuller. 1904. 522 pp. 
WS 104. Underground waters of Gila Valley, Arizona, by W. T. Lee. 1904. 71 pp., 5 pis. 
WS 110. Contributions to the hydrology of eastern United States, 1904; M.L. Fuller, geologist in charge. 1904. 211pp., 5 pis. 



IV SERIES LIST. 

PP 82. Geology and underground water resources of the central Great Plains, by N.H.Darton. 1904. 433pp., 72pls. (Out 

of stock.) 
WS 111. Preliminary report on underground waters of Washington, by Henry Landes. 1904. 85 pp., 1 pi. 
WS 112. Underflow tests in the drainage basin of Los Angeles River, by Homer Hamlin. 1904. 55 pp., 7 pis. 
WS 114. Underground waters of eastern United States, by M. L. Fuller, geologist in charge. 1904. 285 pp., 18 pis. 
WS 118. Geology and water resources of east-central Washington, by F. C. Calkins. 1905. 96 pp., 4 pis. 
B 252. Preliminary report on the geology and water resources of central Oregon, by 1. C. Russell. 1905. 138 pp., 24 pis. 
WS 120. Bibliographic review and index of papers relating to underground waters published by the United States Geo- 
logical Survey, 1879-1904, by M. L. Fuller. 1905. 128 pp. 
WS 122. Relation of the law to underground waters, by D. W. Johnson. 1905. 55 pp. 
WS 123. Geology and underground water conditions of the Jornada del Muerto, New Mexico, by C. R. Keyes. 1905. 42 p.p. 

9 pis. 
WS 136. Underground waters of the Salt River Valley, by W. T. Lee. 1905. 194 pp., 24 pis. 
B 264. Record of deep-well drilling for 1904, by M. L. Fuller, E. F. Lines, and A. C. Veatch. 1905. 106 pp. 
PP 44. Underground water resources of Long Island, New York, by A. C. Veatch and others. 1905. 894 pp., 34 pis. 
WS 137. Development of underground waters in the eastern coastal plain region of southern California, by W. C. Menden- 

hall. 1905. 140 pp., 7 pis. 
WS 138. Development of underground waters in the central coastal plain region of southern California, by W. C. Menden- 

hall. 1905. 162 pp., 5 pis. 
WS 139. Development of underground waters in the western coastal plain region of southern California, by W. C. Menden- 

hall. 1905. 105 pp., 7 pis. 
WS 140. Field measurementsVjf tbe rate of movement of underground waters, by C. S. Slichter. 1905. 122 pp., 15 pis. 
WS 141. Observations on the ground waters of Rio Grande Valley, by C. S. Slichter. 1985. 88 pp., 5 pis. 
WS 142. Hydrology of San Bernardino Valley, California, by W. C. Mendenhall. 1905. 124 pp., 13 pis. 
WS 145. Contributions to the hydrology of eastern United States ; M. L. Fuller, geologist in charge. 1905. 220 pp., 6 pis. 
WS 148. Geology and water resources of Oklahoma, by C. N. Gould. 1905. 178 pp., 22 pis. 
WS 149. Preliminary list of deep borings in the United States, second edition, with additions, by N. H. Darton. 1905. 

175 pp. 
PP 46. Geology and underground water resources of northern Louisiana and southern Arkansas, by A. C. Veatch. 1906. 
WS 153. The underflow in Arkansas Valley in western Kansas, by C. S. Slichter. 1906. 90 pp., 8 pis. 
WS 154. The geology and water resources of the eastern portion of the Panhandle of Texas, by C. N. Gould. 1906. 64 pp., 

15 pis. 
WS 155. Fluctuations of the water level in wells, with special reference to Long Island, New York, by A. C. Veatch. 1906. 
WS 167. Underground water in the valleys of Utah Lake and Jordan River, Utah, by G. B. Richardson. 1906. 81pp.,9pls. 
WS 158. Preliminary report on the geology and underground waters of the Roswell artesian area. New Mexico, by C. A. 

Fisher. 1906. 29 pp., 9 pis. 
PP 52. Geology and underground waters of Arkansas Valley in eastern Colorado, by N. H. Darton. 1906. 90 pp., 28 pis. 
The following papers also relate to this subject: Underground waters of Arkansas Valley in eastern Colorado, by G. K. 
Gilbert, in Seventeenth Annual, Pt. II; Preliminary report on artesian waters of a portion of the Dakotas, by N. H. Darton, 
in Seventeenth Annual, Pt. II; Water resources of Illinois, by Frank Leverett, in Seventeenth Annual, Pt. II; Water 
resources of Indiana and Ohio, by Frank Leverett, in Eighteenth Annual, Pt. IV; New developments in well boring and 
irrigation in eastern South Dakota, by N. H. Darton, in Eighteenth Annual, Pt. IV; Rock waters of Ohio, by Edward 
Orton, in Nineteenth Annual, Pt. IV; Artesian well prospects in the Atlantic coastal plain region, by N. H. Darton, 
Bulletin No. 138. 

Correspondence should be addressed to 

The Dieectob, 

United States Geological Survey, 
July, 1906. Washington, D. C. 

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PROFESSIONAL PAPER NO 52 PLXXV 




